Respiratory therapy systems and methods

ABSTRACT

A passive valve for use as a fixed leak valve. The valve includes a body having an internal chamber, first and second body ports in fluid communication with the chamber with the first port configured for fluid communication with a patient connection and the second body port configured for fluid communication with a ventilator, a body passageway in fluid communication with the chamber and with ambient air exterior of the body, and a check valve seal positioned to seal the body passageway to permit the flow of gas within the chamber through the body passageway to the exterior of the body and to prevent the flow of ambient air exterior of the body through the body passageway into the chamber. In alternative embodiments, the valve is incorporated into the patient connection or constructed as a separate part connectable to the patient connection.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 17/657,925, filed Apr. 4, 2022, which is a continuation of U.S.patent application Ser. No. 17/331,625, filed May 26, 2021, now U.S.Pat. No. 11,291,791, which is a continuation of U.S. patent applicationSer. No. 16/689,041, filed Nov. 19, 2019, now U.S. Pat. No. 11,185,655,which is a continuation of U.S. patent application Ser. No. 14/819,165,filed Aug. 5, 2015, now U.S. Pat. No. 10,518,059, which is acontinuation of U.S. patent Ser. No. 14/803,799, filed Jul. 20, 2015,now U.S. Pat. No. 10,758,699, which is a continuation of U.S. patentapplication Ser. No. 14/749,397, filed Jun. 24, 2015, now U.S. Pat. No.9,956,371, which is a continuation of U.S. patent application Ser. No.14/695,708, filed Apr. 24, 2015, now U.S. Pat. No. 10,046,134, which isa continuation of U.S. patent application Ser. No. 14/667,451, filedMar. 24, 2015, now U.S. Pat. No. 10,245,406, and a continuation of U.S.patent Ser. No. 14/667,480, filed Mar. 24, 2015, now U.S. Pat. No.10,315,002, the disclosures of which are incorporated herein byreference in their entireties.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention is directed generally to a passive leak valve foruse with a ventilator. The passive leak valve is usable as part of apatient circuit or the patient connection, including with a passivepatient circuit or patient connection used with a ventilator operable toassist human patients with breathing and having an integratedcough-assist.

Description of the Related Art

Respiration may be characterized as including both an inspiratory phaseand an exhalation phase. During the inspiratory phase, inspiratory gasesare drawn into the lungs, and during the exhalation phase, exhalationgases are expelled from the lungs.

Mechanical ventilators are used to assist with breathing. Conventionalventilators typically push inspiratory gases including oxygen into thepatient's lungs. Many patients who use a ventilator also need othertypes of assistance related to treating and maintaining their airwaysand lungs. For example, some patients may use a nebulizer to deliverdrugs to their lungs and/or airways. Further, some patients may needhelp clearing secretions from their lungs and/or airways. Suchassistance is typically provided by a conventional suction device. Thus,in additional to a ventilator, many patients require multiple devicesand traveling with such equipment can be particularly problematic.

Currently, to receive cough assistance, a patient must be disconnectedfrom mechanical ventilation, and connected to a separate cough assistdevice. After a cough assist maneuver is performed, the patient must bedisconnected from the cough assist device, and reconnected to themechanical ventilation. Often, suctioning of the patient airway is alsoperformed after the patient has been disconnected from the cough assistdevice and reconnected to the mechanical ventilation to removesecretions not adequately cleared from the patient airway during thecough assist maneuver. To minimize risk of patient hypoxemia during theperiod of time that the patient is not receiving mechanical ventilation,it is a common practice to deliver an elevated level of inspired oxygenbefore removing mechanical ventilation from the patient. Because thisprocess may be tedious, it is often not performed in a manner that ismost advantageous to the patient.

Thus, a need exists for ventilators configured to be portable and/orprovide additional functionality beyond delivering inspiratory gasesinto the patient's lungs. The present application provides these andother advantages as will be apparent from the following detaileddescription and accompanying figures.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a block diagram illustrating an exemplary system that includesa ventilator for use by a human patient.

FIG. 2A is an illustration of a first embodiment of a passive patientcircuit for use with the ventilator of FIG. 1 .

FIG. 2B is a cross-sectional view of a second embodiment of a passivepatient circuit for use with the ventilator of FIG. 1 .

FIG. 2C is an enlarged cross-sectional view of a valve assembly of thepassive patient circuit of FIG. 2B illustrated in a closedconfiguration.

FIG. 2D is an enlarged cross-sectional view of the valve assembly of thepassive patient circuit of FIG. 2B illustrated in an open configuration.

FIG. 2E is an exploded view of a valve assembly of the passive patientcircuit of FIG. 2B.

FIG. 2F is an illustration of an alternative embodiment of the firstembodiment of the passive patient circuit shown in FIG. 2A with the leakvalve incorporated into the patient connection.

FIG. 3A is a cross-sectional view of an embodiment of an active patientcircuit for use with the ventilator of FIG. 1 .

FIG. 3B is an exploded view of a multi-lumen tube assembly of the activepatient circuit of FIG. 3A.

FIG. 3C is an exploded view of an active exhalation valve assembly ofthe active patient circuit of FIG. 3A.

FIG. 3D is an enlarged perspective view of a double bellows member ofthe active exhalation valve assembly of FIG. 3C.

FIG. 3E is an enlarged cross-sectional view of the active patientcircuit of FIG. 3A illustrated with the double bellows member of theactive exhalation valve assembly in a closed position.

FIG. 3F is a first enlarged cross-sectional view of the active patientcircuit of FIG. 3A illustrated with the double bellows member of theactive exhalation valve assembly in an open position.

FIG. 3G is a second enlarged cross-sectional view of the active patientcircuit of FIG. 3A illustrated with the double bellows member of theactive exhalation valve assembly in the open position.

FIG. 4 is block diagram illustrating some exemplary components of theventilator of FIG. 1 .

FIG. 5A is a schematic diagram illustrating some exemplary components ofa ventilator assembly of the ventilator of FIG. 1 with a cough assistvalve of the ventilator assembly depicted in a first configuration.

FIG. 5B is a schematic diagram illustrating the cough assist valve ofthe ventilator assembly in a second configuration.

FIG. 5C is an enlarged portion of the schematic diagram of FIG. 5Ashowing the cough assist valve in the first configuration.

FIG. 5D is an enlarged portion of the schematic diagram of FIG. 5Bshowing the cough assist valve in the second configuration.

FIG. 5E is block diagram illustrating exemplary components of a controlsystem of the ventilator, control signals sent by the control system toexemplary components of the ventilation assembly, and the data signalsreceived by the control system from exemplary components of theventilation assembly.

FIG. 6 is block diagram illustrating some exemplary components of a userinterface of the ventilator of FIG. 1 .

FIG. 7A is a schematic diagram illustrating some exemplary components ofan oxygen assembly of the ventilator of FIG. 1 .

FIG. 7B is block diagram illustrating exemplary control signals sent bythe control system to exemplary components of the oxygen assembly, andthe data signals received by the control system from exemplarycomponents of the oxygen assembly.

FIG. 8A is a block diagram illustrating an adsorption bed of the oxygenassembly during a first phase of a vacuum pressure swing adsorption(“VPSA”) process.

FIG. 8B is a block diagram illustrating the adsorption bed of the oxygenassembly during a second phase of the VPSA process.

FIG. 8C is a block diagram illustrating the adsorption bed of the oxygenassembly during a third phase of the VPSA process.

FIG. 8D is a block diagram illustrating the adsorption bed of the oxygenassembly during a fourth phase of the VPSA process.

FIG. 9 is an illustration of a metering valve of the oxygen assembly.

FIG. 10A is a perspective view of a first side of a first rotary valveassembly of the oxygen assembly.

FIG. 10B is a perspective view of a second side of the first rotaryvalve assembly.

FIG. 10C is a perspective view of the first side of the first rotaryvalve assembly including a shaft of a motor assembly and omitting otherparts of the motor assembly.

FIG. 10D is a perspective view of the second side of the first rotaryvalve assembly with its outer housing and printed circuit board removed.

FIG. 10E is an exploded perspective view of one of four poppet valves ofthe first rotary valve assembly illustrated with an end cap andfasteners.

FIG. 10F is a cross-sectional view of the first rotary valve assemblywith its second and fourth poppet valves open.

FIG. 10G is a cross-sectional view of the first rotary valve assemblywith its first and third poppet valves open.

FIG. 11 is a graph showing pressure and feed flow experienced by a bedof nitrogen adsorbent material of the oxygen generator during the fourphases of the VPSA process.

FIG. 12 is a flow diagram of a method performed by the control system ofthe ventilator of FIG. 1 .

FIG. 13A is an illustration of an optional second rotary valve assemblyof the oxygen assembly depicted with a first one of its four poppetvalves open.

FIG. 13B is an illustration of the optional second rotary valve assemblyof the oxygen assembly depicted with a second one of its four poppetvalves open.

FIG. 13C is an illustration of the optional second rotary valve assemblyof the oxygen assembly depicted with a third one of its four poppetvalves open.

FIG. 13D is an illustration of the optional second rotary valve assemblyof the oxygen assembly depicted with a fourth one of its four poppetvalves open.

FIG. 14A is a graph showing patient airway flow using a prior artventilator during both inspiratory and expiratory phases.

FIG. 14B is a graph showing patient airway pressure using the prior artventilator during both the inspiratory and expiratory phases.

FIG. 15A is a graph showing patient airway flow using the ventilator ofFIG. 1 during both inspiratory and expiratory phases.

FIG. 15B is a graph showing patient airway pressure using the ventilatorof FIG. 1 during both the inspiratory and expiratory phases.

FIG. 16 is a block diagram illustrating an exemplary suction assemblyfor use with the ventilator of FIG. 1 .

FIG. 17A is a perspective view of a cough assist valve of the ventilatorassembly showing an air intake side of the cough assist valve.

FIG. 17B is a perspective view of the cough assist valve showing anexhaust outlet side of the cough assist valve.

FIG. 18A is a cross-sectional view of the cough assist valve in a firstconfiguration used during normal ventilation and an insufflation phaseof a cough.

FIG. 18B is a cross-sectional view of the cough assist valve in a secondconfiguration used during an exsufflation phase of a cough.

FIG. 19A is an exploded perspective view of an end cap assembly of thecough assist valve.

FIG. 19B is an enlarged perspective view of a second side of a seatmember of the end cap assembly of FIG. 19A.

FIG. 19C is an enlarged perspective view of a first side of a seatmember of the end cap assembly of FIG. 19A.

FIG. 20 is a perspective view of a subassembly of the cough assist valveincluding a moving coil actuator, a shaft, and a pair of poppet valveassemblies.

FIG. 21 is an exploded perspective view of one of the poppet valveassemblies of the cough assist valve.

FIG. 22 is an exploded perspective view of a subassembly of the coughassist valve including the shaft, a guide member, and retaining rings.

FIG. 23A is a perspective view of the air intake side of the coughassist valve omitting both its end cap assembly and poppet valveassembly.

FIG. 23B is a perspective view of the exhaust outlet side of the coughassist valve omitting its end cap assembly.

FIG. 24A is a perspective view of a first side of an intake body portionof a housing of the cough assist valve.

FIG. 24B is a perspective view of a second side of the intake bodyportion of the housing of the cough assist valve.

FIG. 25 is a perspective view of an exhaust body portion of a housing ofthe cough assist valve.

FIG. 26 is a pair of graphs with the top graph showing airway pressureduring both insufflation and exsufflation phases of a cough assistmaneuver performed using the ventilator, and the bottom graph showingairway flow rate during both the insufflation and exsufflation phases ofthe cough assist maneuver performed using the ventilator.

FIG. 27 is a side view of a secretion trap.

FIG. 28 is a side view of the secretion trap of FIG. 27 connected toboth a patient connection and a patient circuit connection.

FIG. 29 is a side view of an embodiment of the secretion trap of FIG. 28including a drain.

FIG. 30 is an exploded view of an alternate embodiment of a valveassembly for use in the passive patient circuit of FIG. 2B.

FIG. 31A is an enlarged longitudinal cross-sectional view of the valveassembly of FIG. 30 illustrated in a closed configuration.

FIG. 31B is an enlarged longitudinal cross-sectional view of the valveassembly of FIG. 30 illustrated in an open configuration.

FIG. 31C is an enlarged longitudinal cross-sectional view of the valveassembly of FIG. 31A rotated approximately 45° about its longitudinalaxis from the position depicted in FIG. 31A.

FIG. 32 is a perspective view of a first valve housing of the valveassembly of FIG. 30 .

FIG. 33 is a perspective view of a second valve housing of the valveassembly of FIG. 30 .

FIG. 34A is a longitudinal cross-sectional view of an alternateembodiment of a cough assist valve for use with the ventilator assemblyof FIG. 5A depicted in a first configuration used during normalventilation and an insufflation phase of a cough.

FIG. 34B is a longitudinal cross-sectional view of the cough assistvalve of FIG. 34A depicted in a second configuration used during anexsufflation phase of a cough.

FIG. 35 is an exploded perspective view of an end cap assembly of thecough assist valve of FIG. 34A.

FIG. 36 is a perspective view of a subassembly of the cough assist valveof FIG. 34A including a movable magnet subassembly of an actuator, ashaft, and a pair of poppet valve assemblies.

FIG. 37 is a perspective view of an intake body portion of a housing ofthe cough assist valve of FIG. 34A.

FIG. 38 is a perspective view of an exhaust body portion of a housing ofthe cough assist valve of FIG. 34A.

Like reference numerals have been used in the figures to identify likecomponents.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a block diagram illustrating an exemplary system 10 thatincludes a ventilator 100 with integrated cough assist functionality foruse by a patient 102. The ventilator 100 may be configured to provideboth traditional volume controlled ventilation and pressure controlledventilation. The ventilator 100 has an optional multi-lumen tubeconnection 103, a main ventilator connection 104, and a patient oxygenoutlet 105. The patient 102 has a patient connection 106 (e.g., atracheal tube, a nasal mask, a mouthpiece, and the like) that isconnectable to the main ventilator connection 104 and/or the patientoxygen outlet 105 by a patient circuit 110.

As will be described below, the patient circuit 110 may be implementedas an active patient circuit or a passive patient circuit. Optionally,when the patient circuit 110 is implemented as an active patientcircuit, the patient circuit 110 may include one or more ports 111configured to be connected to the optional multi-lumen tube connection103. The port(s) 111 allow one or more pressure signals 109 to flowbetween the optional multi-lumen tube connection 103 and the patientcircuit 110. As is apparent to those of ordinary skill in the art, apressure signal may be characterized as gas(es) obtained from a fluid(and/or gas) source for which a pressure is to be measured. The gas(es)obtained are at the same pressure as the fluid (and/or gas) source.

The main ventilator connection 104 is configured to provide gases 112that include room air 114 optionally mixed with oxygen. While identifiedas being “room air,” those of ordinary skill in the art appreciate thatthe room air 114 may include air obtained from any source external tothe ventilator 100. The gases 112 may be used as inspiratory gases(during the inspiratory phase of a breath) or insufflation gases usedduring the insufflation phase of a cough. The main ventilator connection104 is configured to receive gases 113, which may include exsufflationgases exhaled by the patient 102 during an exsufflation phase of acough.

The air 114 is received by the ventilator 100 via a patient air intake116. The oxygen that is optionally mixed with the air 114 may begenerated internally by the ventilator 100 and/or received from anoptional low pressure oxygen source 118 (e.g., an oxygen concentrator),and/or an optional high pressure oxygen source 120. When the oxygen isgenerated internally, the ventilator 100 may output exhaust gases (e.g.,nitrogen-rich gas 122) via an outlet vent 124. Optionally, theventilator 100 may include a low pressure oxygen inlet 126 configured tobe coupled to the optional low pressure oxygen source 118 and receiveoptional low pressure oxygen 128 therefrom. The ventilator 100 mayinclude an optional high pressure oxygen inlet 130 configured to becoupled to the optional high pressure oxygen source 120 and receiveoptional high pressure oxygen 132 therefrom.

The patient oxygen outlet 105 is configured to provide doses or pulsesof oxygen 140 to the patient connection 106 (via the patient circuit110) that are synchronized with the patient's breathing. Unlike thegases 112 provided by the main ventilator connection 104, the pulses ofoxygen 140 do not include the air 114.

The gases 112 and/or the pulses of oxygen 140 delivered to the patientcircuit 110 are conducted thereby as inspiratory or insufflation gases108 to the patient connection 106, which at least in part conducts thosegases into the patient's lung(s) 142. Whenever the patient exhalesduring the exhalation phase of a breath or exsufflation phase of acough, exhaled gases 107 enter the patient circuit 110 via the patientconnection 106. Thus, the patient circuit 110 may contain one or more ofthe following gases: the gases 112 provided by the ventilator 100, thepulses of oxygen 140, and the exhaled gases 107. For ease ofillustration, the gases inside the patient circuit 110 will be referredto hereafter as “patient gases.”

Optionally, the ventilator 100 includes a suction connection 150configured to be coupled to an optional suction assembly 152. Theventilator 100 may provide suction 154 to the optional suction assembly152 via the optional suction connection 150. The suction assembly 152may be configured to be connected to the patient connection 106, asuction catheter 812 (see FIG. 16 ) positionable inside the patientconnection 106, and/or a drain 1280 (see FIG. 29 ).

Referring to FIG. 1 , optionally, the ventilator 100 includes anebulizer connection 160 configured to be coupled to an optionalnebulizer assembly 162. The ventilator 100 may provide gases 164 (e.g.,the air 114) to the optional nebulizer assembly 162 via the optionalnebulizer connection 160. The optional nebulizer assembly 162 may beconfigured to be connected to the patient circuit 110. However, this isnot a requirement.

Optionally, the ventilator 100 may include an outlet port 166 throughwhich exhaust 167 may exit from the ventilator 100.

The ventilator 100 may be configured to be portable and powered by aninternal battery (not shown) and/or an external power source (not shown)such as a conventional wall outlet.

Passive Patient Circuits

FIG. 2A is an illustration of a first embodiment of a passive patientcircuit 170 that may be used to implement the patient circuit 110.Referring to FIG. 2A, the passive patient circuit 170 has a first endportion 172 opposite a second end portion 174. The first end portion 172is configured to be connected or coupled (e.g., directly or using ahose, flow line, conduit, or tube) to the main ventilator connection104. The second end portion 174 is configured to be connected or coupledto the patient connection 106 (e.g., directly or using a hose, flowline, conduit, or tube). Optionally, a secretion trap 1250 (describedbelow with respect to FIGS. 27-29 ) may be positioned between the secondend portion 174 and the patient connection 106. The passive patientcircuit 170 conducts the gases 112 (that include the air 114 optionallymixed with oxygen) from the main ventilator connection 104 into thepatient connection 106 (optionally via the secretion trap 1250illustrated in FIGS. 27-29 ).

In the embodiment illustrated, the passive patient circuit 170 includesan optional bacterial filter 176, a leak valve 177, and a flexible tubesegment 178. The optional bacterial filter 176 may be positioned betweenthe first end portion 172 and the flexible tube segment 178. The gases112 may flow through the optional bacterial filter 176 and on to thepatient connection 106. When present, the bacterial filter 176 helpsprevent bacteria (e.g., received from the patient connection 106) fromentering the ventilator 100 (via the main ventilator connection 104).

The leak valve 177 is coupled to the flexible tube segment 178 near thesecond end portion 174. The leak valve 177 is configured to allow gasesto flow out of the passive patient circuit 170 and into the environmentoutside the passive patient circuit 170. The leak valve 177 may beimplemented as a conventional fixed leak valve configured to allow atmost a threshold amount of pressure inside the passive patient circuit170 during both the inspiratory and exhalation phases.

The leak valve 177 may be implemented as a positive pressure valve thatallows a portion of the patient gases to flow out of the passive patientcircuit 170 and into the environment outside the passive patient circuit170 whenever the pressure inside the passive patient circuit 170 isabove the threshold amount (e.g., environmental pressure). The leakvalve 177 includes a flexible member or flap 179 that covers and sealsan outlet opening 180 when the pressure inside the passive patientcircuit 170 is below the threshold amount. Thus, the leak valve 177 isclosed when the pressure inside the passive patient circuit 170 is belowthe threshold amount.

On the other hand, the flap 179 is configured to be pushed outwardly andaway from the outlet opening 180 when the pressure inside the passivepatient circuit 170 exceeds the threshold amount (e.g., environmentalpressure). Thus, the leak valve 177 is open when the pressure inside thepassive patient circuit 170 is above the threshold amount. During normalventilation, the leak valve 177 is open during both the inspiratory andexhalation phases. This means a portion of the patient gases inside thepassive patient circuit 170 flow out of the passive patient circuit 170through the outlet opening 180 and into the environment outside thepassive patient circuit 170 during both the inspiratory and exhalationphases. On the other hand, as explained below, during an exsufflationphase of a cough, the leak valve 177 closes. This prevents the patientgases inside the passive patient circuit 170 from flowing out of thepassive patient circuit 170 through the outlet opening 180. It alsoprevents air from entering the passive patient circuit 170 through theoutlet opening 180.

FIG. 2F is an illustration of an alternative embodiment of the firstembodiment of the passive patient circuit 170 shown in FIG. 2A with theleak valve 177 incorporated into the patient connection 106 and to whichthe second end portion 174 of the flexible tube segment 178 is connectedor coupled. Alternatively, the leak valve 177 may be constructed as aseparate part connected or coupled both to the second end portion 174 ofthe flexible tube segment 178 and to the patient connection 106.

FIG. 2B is an illustration of a second embodiment of a passive patientcircuit 440 that may be used to implement the patient circuit 110. Thepassive patient circuit 440 includes a connector 442, a flexible tubesegment 444, an open-ended oxygen pulse delivery tube 446, and a valveassembly 448. The flexible tube segment 444 may be implemented using aconventional corrugated or expanding ventilation hose or tubing (e.g.,circuit tubing). The flexible tube segment 444 has a first end portion450 opposite a second end portion 451. The first end portion 450 isconfigured to be connected or coupled to the connector 442. The secondend portion 451 is configured to be connected or coupled to the valveassembly 448.

The connector 442 has a generally tube-shaped connector housing 452 witha first end portion 454 configured to be connected to the mainventilator connection 104 (e.g., directly or using a hose, flow line,conduit, or tube) and to receive the gases 112 (that include the air 114optionally mixed with oxygen) from the main ventilator connection 104.Optionally, the bacterial filter 176 (see FIG. 2A) may be positionedbetween the connector 442 and the main ventilator connection 104. Insuch embodiments, the gases 112 flow through the bacterial filter 176 ontheir way to the connector 442. The bacterial filter 176 helps preventbacteria (e.g., received from the patient connection 106) from enteringthe ventilator 100 (via the main ventilator connection 104).

The connector housing 452 has a second end portion 456 configured to becoupled to the first end portion 450 of the flexible tube segment 444and to provide the gases 112 received by the first end portion 454 tothe flexible tube segment 444. The flexible tube segment 444 conductsthe gases 112 to the valve assembly 448.

The connector 442 includes a hollow tube section 458 that extendsoutwardly from the connector housing 452. In the embodiment illustrated,the tube section 458 is substantially transverse to the connectorhousing 452. However, this is not a requirement. The tube section 458has an open free end portion 459 configured to be connected to thepatient oxygen outlet 105 (e.g., directly or using a hose, flow line,conduit, or tube) and to receive the pulses of oxygen 140 therefrom.Inside the connector housing 452, the tube section 458 is connected tothe oxygen pulse delivery tube 446 and provides the pulses of oxygen 140thereto. In the embodiment illustrated, the tube section 458 isconnected to or includes a branch tube 460 that extends longitudinallyinside the connector housing 452. The branch tube 460 has an open freeend 462 configured to be coupled to the oxygen pulse delivery tube 446and provide the pulses of oxygen 140 thereto. While the tube section 458extends into the connector housing 452, the tube section 458 onlypartially obstructs the flow of the gases 112 through the connectorhousing 452. In other words, the gases 112 pass by or alongside the tubesection 458 and the branch tube 460, if present.

In the embodiment illustrated, the oxygen pulse delivery tube 446extends through the flexible tube segment 444 and at least part way intothe valve assembly 448. Thus, the oxygen pulse delivery tube 446isolates the pulses of oxygen 140 from the gases in the flexible tubesegment 444 along a majority portion of the passive patient circuit 440.The oxygen pulse delivery tube 446 has a first end portion 464configured to be coupled to the branch tube 460. The oxygen pulsedelivery tube 446 has a second end portion 465 that terminates at ornear the patient connection 106. By way of a non-limiting example, thesecond end portion 465 may terminate within about two centimeters of thepatient connection 106. The oxygen pulse delivery tube 446 conducts thepulses of oxygen 140 from the branch tube 460 to the patient connection106. At the same time, the passive patient circuit 440 conducts thegases 112 (that include the air 114 optionally mixed with oxygen) fromthe main ventilator connection 104 into the patient connection 106.

In alternate embodiments, the oxygen pulse delivery tube 446 may beconnected to the patient oxygen outlet 105 (e.g., directly or using ahose, flow line, conduit, or tube) to receive the pulses of oxygen 140from the patient oxygen outlet 105. In such embodiments, the oxygenpulse delivery tube 446 may extend along the outside of the flexibletube segment 444. The second end portion 465 of the oxygen pulsedelivery tube 446 may be connected to a portion of the passive patientcircuit 440 at or near the patient connection 106 to provide the pulsesof oxygen 140 from the branch tube 460 to the patient connection 106.

FIGS. 2C-2E illustrate exemplary components of the valve assembly 448.In the embodiment illustrated, the valve assembly 448 includes a firstvalve housing 468, a second valve housing 469, and a flexiblering-shaped leaf 470.

The first valve housing 468 is configured to be coupled to the patientconnection 106 (see FIG. 2A). Optionally, the secretion trap 1250 (seeFIGS. 27 and 28 ) may be coupled between the first valve housing 468 andthe patient connection 106. The second valve housing 469 is configuredto be coupled to the second end portion 451 of the flexible tube segment444. The first and second valve housings 468 and 469 are configured tobe coupled together with the ring-shaped leaf 470 positionedtherebetween. A peripheral portion 473 of the leaf 470 is positionedwithin a ring-shaped chamber 474 defined by the first and second valvehousings 468 and 469. One or more openings 476 are formed in the secondvalve housing 469 and connect the chamber 474 with the environmentoutside the passive patient circuit 440 (see FIG. 2B). Additionally, oneor more openings 478 are formed in the second valve housing 469 andconnect the patient gases inside the passive patient circuit 440 (seeFIG. 2B) with the chamber 474.

Like the flap 179 (see FIG. 2A), the peripheral portion 473 of the leaf470 is configured to transition or deflect from a closed position (seeFIG. 2C) and an open position (see FIG. 2D) when the pressure inside thepassive patient circuit 440 (see FIG. 2B) exceeds the threshold amount(e.g., environmental pressure). When the peripheral portion 473 of theleaf 470 is in the closed position depicted in FIG. 2C, the leaf 470blocks off the one or more openings 478 and isolates the chamber 474from the environment inside the passive patient circuit 440 (see FIG.2B). On the other hand, when the peripheral portion 473 of the leaf 470is in the open position depicted in FIG. 2D, the leaf 470 no longerblocks off the one or more openings 478 and allows the chamber 474 tocommunicate with the patient gases inside and outside the passivepatient circuit 440 (see FIG. 2B). Thus, gases may exit the interior ofthe passive patient circuit 440 (see FIG. 2B) through the opening(s)478, the chamber 474, and the opening(s) 476.

During the inspiratory phase, the ventilator 100 adjusts the pressureinside the passive patient circuit 440 to achieve a preset inspiratorypressure, which places or maintains the peripheral portion 473 of theleaf 470 in the open position with the peripheral portion 473 of theleaf leaving the openings 478 unblocked. Some of the patient gases flowto the patient 102 (see FIG. 1 ), and some of the patient gases flow outthrough the openings 476.

During the exhalation phase, the ventilator 100 adjusts the pressureinside the passive patient circuit 440 to achieve a baseline or positiveend-expiratory pressure (“PEEP”), which places or maintains theperipheral portion 473 of the leaf 470 in the open position. Some of theexhaled gases 107 (see FIG. 1 ) from the patient 102 flow out throughthe openings 476, and some of the exhaled gases 107 flow into thepassive patient circuit 440 (e.g., into the flexible tube segment 444).

The breath may pause between the end of the exhalation phase and thebeginning of the inspiratory phase. This pause may be characterized as adead time that occurs between the phases. During a pause, the ventilator100 adjusts the pressure inside the passive patient circuit 440 to PEEP,which places or maintains the peripheral portion 473 of the leaf 470 inthe open position, and causes the flow of the gases 112 from theventilator 100 to flow out of the passive patient circuit 440 throughthe openings 476. Also, during this time, at least a portion of theexhaled gases 107 that flowed into the passive patient circuit 440during the exhalation phase is “purged” out through the openings 476 bythe forward moving flow of the gases 112 from the ventilator 100.

As explained below, during an exsufflation phase of a cough, thepressure inside the passive patient circuit 440 (see FIG. 2B) is lessthan the threshold amount (e.g., environmental pressure). This placesthe peripheral portion 473 of the leaf 470 in the closed position withthe peripheral portion 473 of the leaf blocking the openings 478, whichprevents the patient gases inside the passive patient circuit 440 fromflowing out of the passive patient circuit 440 through the opening(s)476. It also prevents air from entering the passive patient circuit 440through the opening(s) 476.

The combined areas of the openings 476 may be characterized as providinga fixed orifice. Thus, the valve assembly 448 may be characterized asbeing a one-way valve with a fixed orifice. If the combined areas of theopenings 476 is too large, most of the inspiratory flow will leak outthrough the openings 476, leaving little for the patient 102.Conversely, if the combined areas of the openings 476 is too small, theexhaled gases 107 will not be fully purged from the passive patientcircuit 440 during the exhalation phase and the pause between theinspiratory and exhalation phases. By way of a non-limiting example, thevalve assembly 448 may be configured to leak about 20-50 liters perminute (“LPM”) when the pressure inside the passive patient circuit 440is about 10 centimeters of water (“cmH20”).

FIG. 30 is an exploded view of an alternate embodiment of a valveassembly 1448 that may be used in the passive patient circuit 440 (seeFIG. 2B) instead of the valve assembly 448. In such embodiments, theflexible tube segment 444 (see FIG. 2B) conducts the gases 112 (see FIG.2B) to the valve assembly 1448 and the oxygen pulse delivery tube 446may extend through the flexible tube segment 444 (see FIG. 2B) and atleast part way into the valve assembly 1448.

In the embodiment illustrated, the valve assembly 1448 includes a firstvalve housing 1468, a second valve housing 1469, and a flexiblering-shaped leaf 1470. As shown in FIGS. 31A-31C, the first and secondvalve housings 1468 and 1469 are configured to be coupled together withthe ring-shaped leaf 1470 positioned therebetween.

Referring to FIG. 32 , in the embodiment illustrated, the first valvehousing 1468 has a first end portion 1480 opposite a second end portion1482. An open ended through channel 1484 extends through the first valvehousing 1468 between its first and second end portions 1480 and 1482.The first end portion 1480 is configured to be coupled to the patientconnection 106 (see FIG. 2B). Optionally, the secretion trap 1250 (seeFIGS. 27-29 ) may be coupled between the first end portion 1480 of thefirst valve housing 1468 and the patient connection 106 (see FIG. 2B).

The second end portion 1482 is configured to be coupled to the secondvalve housing 1469 (see FIGS. 30-31C and 33 ). The second end portion1482 includes a ring-shaped longitudinally extending inner wall 1486positioned alongside the channel 1484 and defining a portion thereof.The second end portion 1482 includes a first wall portion 1488 thatextends radially outwardly from the inner wall 1486 and terminates at aring-shaped longitudinally extending outer wall 1489. The outer wall1489 is concentric with and spaced apart from the inner wall 1486 by thefirst wall portion 1488. A distal edge portion 1487 of the inner wall1486 is configured to abut the leaf 1470 (see FIGS. 30-31C) and pressthe leaf 1470 against the second valve housing 1469 (see FIGS. 30-31Cand 33 ) to form an annular seal between the first and second valvehousings 1468 and 1469 along the distal edge portion 1487 of thering-shaped inner wall 1486. Near the location whereat the outer wall1489 terminates the first wall portion 1488, the outer wall 1489 has aring-shaped groove 1490 formed along its inner surface that opens towardthe inner wall 1486. The outer wall 1489 has a longitudinally extendingnotch or keyway 1491 formed therein.

Referring to FIG. 33 , in the embodiment illustrated, the second valvehousing 1469 has a first end portion 1420 opposite a second end portion1422. An open ended through channel 1424 extends through the secondvalve housing 1469 between its first and second end portions 1420 and1422. The second end portion 1422 of the second valve housing 1469 isconfigured to be coupled to the second end portion 451 (see FIG. 2B) ofthe flexible tube segment 444 (see FIG. 2B).

The first end portion 1420 is configured to be coupled to the firstvalve housing 1468 (see FIGS. 30-32 ). The first end portion 1420 of thesecond valve housing 1469 includes a radially outwardly extending secondwall portion 1428 having a distal portion 1429. A plurality of tabs1430A-1430D are positioned along the distal portion 1429 of the secondwall portion 1428. The tabs 1430A-1430D are configured to be receivedinside the ring-shaped groove 1490 (see FIG. 32 ) formed in the outerwall 1489 (see FIG. 32 ) of the first valve housing 1468 (see FIGS.30-32 ). Engagement between the tabs 1430A-1430D and the groove 1490couples the first and second valve housings 1468 and 1469 together. Thetab 1430D includes a key member 1432 configured to be received insidethe keyway 1491 (see FIG. 32 ) formed in the outer wall 1489 (see FIG.32 ) of the first valve housing 1468 (see FIGS. 30-32 ). When the firstand second valve housings 1468 and 1469 are coupled together, the keymember 1432 is received inside the keyway 1491 to prevent rotation ofthe first valve housing 1468 relative to the second valve housing 1469.

The second valve housing 1469 includes a plurality of leaf positioningprojections 1434A-1434D configured to be received inside a centralthrough-hole 1436 (see FIG. 30 ) formed in the leaf 1470 (see FIGS.30-31B). Referring to FIG. 31C, the leaf positioning projections1434A-1434D help position the leaf 1470 with respect to the first andsecond valve housings 1468 and 1469. When the first and second valvehousings 1468 and 1469 are coupled together, the leaf positioningprojections 1434A-1434D extend into the channel 1484 (see FIG. 32 )alongside the inner wall 1486 (see FIG. 32 ).

Referring to FIGS. 31A-31C, a peripheral portion 1473 of the leaf 1470is positioned within a ring-shaped chamber 1474 defined by the first andsecond valve housings 1468 and 1469. Referring to FIGS. 31A and 31B, inthe embodiment illustrated, the chamber 1474 is defined by the innerwall 1486, the first wall portion 1488, the outer wall 1489, and thesecond wall portion 1428.

One or more openings 1476 are defined between the first and second valvehousings 1468 and 1469. In the embodiment illustrated, the second wallportion 1428 extends only partway toward the outer wall 1489 of thefirst valve housing 1468. However, as shown in FIG. 31C, the tabs1430A-1430D (see FIG. 33 ), which are mounted on the distal portion 1429(see FIG. 33 ) of the second wall portion 1428, contact the outer wall1489 of the first valve housing 1468. Thus, referring to FIGS. 31A and31B, the openings 1476 are defined between the distal portion 1429 (seeFIG. 33 ) of the second wall portion 1428 and the outer wall 1489 of thefirst valve housing 1468 and positioned between the tabs 1430A-1430D(see FIG. 33 ).

The one or more openings 1476 connect the chamber 1474 with theenvironment outside the passive patient circuit 440 (see FIG. 2B).Additionally, one or more openings 1478 are formed in the second valvehousing 1469 and connect the patient gases inside the passive patientcircuit 440 (see FIG. 2B) with the chamber 1474. Referring to FIG. 33 ,the one or more openings 1478 are positioned between the distal portion1429 of the second wall portion 1428 and the leaf positioningprojections 1434A-1434D.

Referring to FIGS. 31A-31C, the flexible ring-shaped leaf 1470 issubstantially similar to the flexible ring-shaped leaf 470 (see FIGS.2C-2E). The peripheral portion 1473 of the leaf 1470 is configured totransition or deflect from a closed position (see FIGS. 31A and 31C) andan open position (see FIG. 31B) when the pressure inside the passivepatient circuit 440 (see FIG. 2B) exceeds the threshold amount (e.g.,environmental pressure). When the peripheral portion 1473 of the leaf1470 is in the closed position depicted in FIGS. 31A and 31C, the leaf1470 blocks off the one or more openings 1478 into the chamber 1474thereby isolating the chamber 1474 from the environment inside thepassive patient circuit 440 (see FIG. 2B). On the other hand, when theperipheral portion 1473 of the leaf 1470 is in the open positiondepicted in FIG. 31B, the leaf 1470 no longer blocks off the one or moreopenings 1478 and allows the chamber 1474 to communicate with thepatient gases inside the passive patient circuit 440 (see FIG. 2B).Thus, gases may exit the interior of the passive patient circuit 440(see FIG. 2B) through the opening(s) 1478, the chamber 1474, and theopening(s) 1476.

As mentioned above, during the inspiratory phase, the ventilator 100adjusts the pressure inside the passive patient circuit 440 to achieve apreset inspiratory pressure, which places or maintains the peripheralportion 1473 of the leaf 1470 in the open position (see FIG. 31B). Someof the patient gases flow to the patient 102 (see FIG. 1 ), and some ofthe patient gases flow out through the openings 1476.

During the exhalation phase, the ventilator 100 adjusts the pressureinside the passive patient circuit 440 to achieve a baseline or positiveend-expiratory pressure (“PEEP”), which places or maintains theperipheral portion 1473 of the leaf 1470 in the open position (see FIG.31B). Some of the exhaled gases 107 (see FIG. 1 ) from the patient 102flow out through the openings 1476, and some of the exhaled gases 107flow into the passive patient circuit 440 (e.g., into the flexible tubesegment 444).

During a pause between the end of the exhalation phase and the beginningof the inspiratory phase, the ventilator 100 adjusts the pressure insidethe passive patient circuit 440 to PEEP, which places or maintains theperipheral portion 1473 of the leaf 1470 in the open position (see FIG.31B), and causes the flow of the gases 112 from the ventilator 100 toflow out of the passive patient circuit 440 through the openings 1476.Also, during this time, at least a portion of the exhaled gases 107 thatflowed into the passive patient circuit 440 during the exhalation phaseis “purged” out through the openings 1476 by the forward moving flow ofthe gases 112 from the ventilator 100.

The combined areas of the openings 1476 may be characterized asproviding a fixed orifice. Thus, the valve assembly 1448 may becharacterized as being a one-way valve with a fixed orifice. If thecombined areas of the openings 1476 is too large, most of theinspiratory flow will leak out through the openings 1476, leaving littlefor the patient 102. Conversely, if the combined areas of the openings1476 is too small, the exhaled gases 107 will not be fully purged fromthe passive patient circuit 440 during the exhalation phase and thepause between the inspiratory and exhalation phases. By way of anon-limiting example, the valve assembly 1448 may be configured to leakabout 20-50 LPM when the pressure inside the passive patient circuit 440is about 10 cmH20.

As explained below, during an exsufflation phase of a cough, thepressure inside the passive patient circuit 440 (see FIG. 2B) is lessthan the threshold amount (e.g., environmental pressure). When thepassive patient circuit 440 (see FIG. 2B) includes the valve assembly1448 (instead of the valve assembly 448), the peripheral portion 1473 ofthe leaf 1470 is placed in the closed position (see FIGS. 31A and 31C)when the pressure inside the passive patient circuit 440 (see FIG. 2B)is less than the threshold amount, which prevents the patient gasesinside the passive patient circuit 440 from flowing out of the passivepatient circuit 440 through the opening(s) 1476. It also prevents airfrom entering the passive patient circuit 440 through the opening(s)1476.

It should be noted that the passive valve assemblies described hereinmay be integrated into the patient connection 106, such as into apatient mask serving as the patient connection, rather than being partof the passive patient circuit 170 or the passive patient circuit 440.As stated above and as shown in FIG. 1 , the patient 102 has a patientconnection 106 which may be a tracheal tube, a nasal mask, a mouthpieceor the like, that is connectable to the main ventilator connection 104and/or the patient oxygen outlet 105 by a patient circuit 110.

Active Patient Circuit

FIG. 3A depicts an active patient circuit 600 that may be used toimplement the patient circuit 110 (see FIG. 1 ). Referring to FIG. 3A,the active patient circuit 600 includes the connector 442, the flexibletube segment 444, the oxygen pulse delivery tube 446, a multi-lumen tubeassembly 602, and an active exhalation valve assembly 604.

Like in the passive patient circuit 440 (see FIG. 2B), the connector 442is coupled to both the first end portion 450 of the flexible tubesegment 444 and the oxygen pulse delivery tube 446. The connector 442receives the gases 112 and provides them to the flexible tube segment444. Further, the connector 442 receives the pulses of oxygen 140 andprovides them to the oxygen pulse delivery tube 446. The pulses ofoxygen 140 exit the oxygen pulse delivery tube 446 at or near thepatient connection 106. By way of a non-limiting example, the pulses ofoxygen 140 may exit the oxygen pulse delivery tube 446 within about 10centimeters of the patient connection 106. In the embodimentillustrated, the pulses of oxygen 140 exit the oxygen pulse deliverytube 446 at or near the active exhalation valve assembly 604.

Optionally, the bacterial filter 176 (see FIG. 2A) may be positionedbetween the connector 442 and the main ventilator connection 104. Insuch embodiments, the gases 112 flow through the bacterial filter 176 ontheir way to the connector 442. When present, the bacterial filter 176helps prevent bacteria (e.g., received from the patient connection 106)from entering the ventilator 100 (via the main ventilator connection104).

The second end portion 451 of the flexible tube segment 444 isconfigured to be coupled to the active exhalation valve assembly 604. Asmentioned above with respect to FIG. 1 , the patient circuit 110 mayinclude one or more ports 111 configured to allow the one or morepressure signals 109 to flow between the optional multi-lumen tubeconnection 103 and the patient circuit 110. Referring to FIG. 3C, in theembodiment illustrated, the ports 111 (see FIG. 1 ) include ports111A-111C spaced apart from one another longitudinally. The ports111A-111C are each formed in the active exhalation valve assembly 604.The port 111C is referred to hereafter as the pilot port 111C.

FIG. 3B is exploded perspective view of the multi-lumen tube assembly602. Referring to FIG. 3B, the multi-lumen tube assembly 602 includes acoupler 608, an elongated tube segment 610, and a connector member 612.The coupler 608 is configured to couple a first end portion 620 of thetube segment 610 to the optional multi-lumen tube connection 103 (seeFIG. 3A). The tube segment 610 has a second end portion 622 opposite thefirst end portion 620. The second end portion 622 is connected to theconnector member 612. Three separate and continuous open-ended channels626A-626C extend longitudinally through the tube segment 610.

The connector member 612 has three connectors 630A-630C configured toconnected to the ports 111A-111C (see FIG. 3C), respectively. Theconnectors 630A and 630B receive pressure signals 109A and 109B (seeFIG. 5A), respectively, from the ports 111A and 111B, respectively. Theconnector 630C conducts a pressure signal 109C (see FIG. 5A) to and fromthe pilot port 111C.

Continuous channels 632A-632C extend from the connectors 630A-630C,respectively, to an end portion 634 of the connector member 612. Whenthe connector member 612 is connected to the tube segment 610, thecontinuous channels 626A-626C of the tube segment 610 are aligned andcommunicate with the continuous channels 632A-632C, respectively. Thus,the multi-lumen tube assembly 602 may be used to conduct the separatepressure signals 109A and 109B, respectively, from the ports 111A and111B, respectively, to the optional multi-lumen tube connection 103.Further, the multi-lumen tube assembly 602 may be used to conduct thepressure signal 109C to the pilot port 111C from the optionalmulti-lumen tube connection 103 and vice versa.

Referring to FIG. 3C, the active exhalation valve assembly 604 includesa first valve housing member 640, a double bellows member 644, and asecond valve housing member 642. The ports 111A and 111B are formed inthe first valve housing member 640 and extend laterally outwardlytherefrom. The pilot port 111C is formed in the second valve housingmember 642 and extends laterally outwardly therefrom.

FIGS. 3E and 3F are enlarged longitudinal cross sectional views thateach show a portion of the active patient circuit 600 that includes theactive exhalation valve assembly 604. The oxygen pulse delivery tube 446has been omitted from FIGS. 3E and 3F. In the embodiment illustrated,the first valve housing member 640 includes an internal obstruction 646positioned between the ports 111A and 111B and configured to partiallyrestrict flow through the first valve housing member 640. Further, asshown in FIGS. 3E and 3F, the interior of the first valve housing member640 includes a first narrowed portion 647A that is adjacent to theobstruction 646 and the port 111A, and a second narrowed portion 647Bthat is adjacent to the obstruction 646 and the port 111B. Thus, thefirst and second narrowed portions 647A and 647B are positioned oppositeone another longitudinally with respect to the obstruction 646 with thefirst narrowed portion 647A being nearer to the patient connection 106(see FIG. 3A) than the second narrowed portion 647B. The ports 111A and111B open into the first and second narrowed portions 647A and 647B,respectively.

Referring to FIG. 3G, together the obstruction 646, the first and secondnarrowed portions 647A and 647B, and the ports 111A and 111B define anairway flow transducer 648 (e.g., a fixed orifice differential pressuretype flow meter) inside the interior of the first valve housing member640. During the inspiration phase, the gases 112 may flow around theobstruction 646 along flow paths identified by curved arrows 649A and649B. During the exhalation phase, the exhaled gases 107 may flow aroundthe obstruction 646 along flow paths opposite those identified by thecurved arrows 649A and 649B.

Referring to FIG. 3C, the first valve housing member 640 has a first endportion 650 configured to be coupled to the patient connection 106 (seeFIG. 3A). Optionally, the secretion trap 1250 (see FIGS. 27 and 28 ) maybe coupled between the first end portion 650 and the patient connection106. The first valve housing member 640 has a second end portion 652configured to be coupled to the second valve housing member 642. Thesecond valve housing member 642 has a first end portion 654 configuredto be coupled to the second end portion 652 of the first valve housingmember 640, and a second end portion 656 configured to be coupled to thesecond end portion 451 of the flexible tube segment 444. The first endportion 654 of the second valve housing member 642 has a generallycylindrical shaped bellows connector portion 657. An opening 658 of thepilot port 111C is formed in the bellows connector portion 657 of thesecond valve housing member 642.

Referring to FIG. 3D, the double bellows member 644 has a generallyring-like outer shape with a centrally located through-channel 660. Thedouble bellows member 644 has a hollow interior 662 with a ring-shapedopen end 664 opposite a ring-shaped closed end 666 (see FIG. 3C). In theembodiment illustrated, the double bellows member 644 has concertinaedinner and outer sidewalls 668 and 669. The inner sidewall 668 extendsbetween the open end 664 and the closed end 666 along the centrallylocated through-channel 660. The outer sidewall 669 extends between theopen end 664 and the closed end 666 and is spaced radially outwardlyfrom the inner sidewall 668. The hollow interior 662 is defined betweenthe inner and outer sidewalls 668 and 669. Each of the inner and outersidewalls 668 and 669 have bellows portions 668A and 669A (see FIG. 3C),respectively, which each have an undulating longitudinal cross-sectionalshape. In alternate embodiments, the inner and outer sidewalls 668 and669 may include different numbers of convolutions that define a singleconvolute or more than two convolutes.

The open end 664 is configured to fit over the bellows connector portion657 of the second valve housing member 642 like a sleeve. When thebellows connector portion 657 of the second valve housing member 642 isreceived inside the open end 664 of the double bellows member 644, thebellows portions 668A and 669A (see FIG. 3C) of the inner and outersidewalls 668 and 669, respectively, are positioned adjacent to thebellows connector portion 657 of the second valve housing member 642.Thus, the opening 658 of the pilot port 111C is in communication with aportion of the hollow interior 662 positioned between the bellowsportions 668A and 669A (see FIG. 3C) of the inner and outer sidewalls668 and 669, respectively.

Referring to FIG. 3C, when the bellows connector portion 657 of thesecond valve housing member 642 is received inside the open end 664 ofthe double bellows member 644, the opening 658 of the pilot port 111Cmay provide the pressure signal 109C to the interior of the doublebellows member 644.

Referring to FIGS. 3E and 3F, as mentioned above, the second end portion652 of the first valve housing member 640 is configured to be coupled tothe first end portion 654 of the second valve housing member 642. Whenso coupled together, a ring-shaped chamber 670 is defined between thesecond end portion 652 of the first valve housing member 640 and thefirst end portion 654 of the second valve housing member 642. One ormore openings 672 (see FIG. 3C) are formed in the first valve housingmember 640 and connect the chamber 670 with the environment outside theactive patient circuit 600 (see FIG. 3A). The bellows portion 668A and669A (see FIG. 3C) of the outer sidewall 669 and a peripheral portion674 of the closed end 666 is positioned within the chamber 670.

The double bellows member 644 is constructed from a flexible material(e.g., silicone rubber and the like). The bellows portions 668A and 669A(see FIG. 3C) of the inner and outer sidewalls 668 and 669,respectively, are configured to compress to transition the closed end666 from a closed position (see FIG. 3E) to an open position (see FIG.3F). When the bellows portions 668A and 669A (see FIG. 3C) are notcompressed, the closed end 666 is in the closed position depicted inFIG. 3E. In this configuration, the closed end 666 of the double bellowsmember 644 abuts a ring-shaped seat 680 formed in the first valvehousing member 640 and defining a portion of the chamber 670. This sealsthe chamber 670 from the interior of the active patient circuit 600. Onthe other hand, when the bellows portions 668A and 669A (see FIG. 3C)are compressed toward the second valve housing member 642, the closedend 666 is in the open position depicted in FIG. 3F. In thisconfiguration, the closed end 666 is spaced away from the seat 680. Thisopens the chamber 670 by connecting the chamber 670 with the inside ofthe active patient circuit 600. Thus, when the closed end 666 of thedouble bellows member 644 is in the open position, patient gases insidethe active patient circuit 600 may exit therefrom through the chamber670 and the opening(s) 672 (see FIG. 3C).

The closed end 666 of the double bellows member 644 is selectively movedbetween the open and closed positions by controlling the pressure insidethe double bellows member 644 using the pilot port 111C. For example,the closed end 666 of the double bellows member 644 may be placed in theclosed position (see FIG. 3E) during the inspiratory phase, and in theopen position during the expiratory phase. In such embodiments, at thestart of the inspiratory phase, the pilot port 111C provides a flow ofgases (as the pressure signal 109C) having the same pressure as thegases 112 (provided to the active patient circuit 600) to the hollowinterior 662 of the double bellows member 644. An area of the doublebellows member 644 exposed to a pressure provided by the patient 102(see FIG. 1 ) via the patient connection 106 is less than an areaexposed to the pressure of the pressure signal 109C, so that even if thetwo pressures are equal, the closed end 666 of the double bellows member644 will move to or remain in the closed position against the seat 680.At the end of the inspiratory phase, the pilot port 111C provides a flowof gases (as the pressure signal 109C) having a pilot pressure to thehollow interior 662 of the double bellows member 644. The pilot pressureis less than the pressure provided by the patient 102 (see FIG. 1 ) viathe patient connection 106 and causes the closed end 666 of the doublebellows member 644 to move to or remain in the open position (see FIG.3F) spaced apart from the seat 680. Thus, during normal ventilation, thepressure inside the hollow interior 662 of the double bellows member 644may be alternated between a closed pressure that is the same pressure asthe gases 112 (provided to the active patient circuit 600), and an openpressure that is equal to the pilot pressure. If desired, the pressureinside the hollow interior 662 of the double bellows member 644 may beadjusted by allowing the flow of gases (in the pressure signal 109C) toflow from the hollow interior 662 to the pilot port 111C.

As explained below, during an exsufflation phase of a cough, the closedend 666 of the double bellows member 644 may be placed in the closedposition (see FIG. 3E). This prevents exsufflation gases (exhaled by thepatient 102) into the active patient circuit 600 from exiting the activepatient circuit 600 through the opening(s) 672 (see FIG. 3C). It alsoprevents air from entering the active patient circuit 600 through theopening(s) 672 (see FIG. 3C). It is noted that during the beginning ofthe exsufflation phase, when the pressure is still positive, the doublebellows member 644 is in the open position and automatically closes whenthe pressure provided by the patient 102 drops below ambient.

Ventilator

FIG. 4 is a block diagram illustrating some exemplary components of theventilator 100. Referring to FIG. 4 , in addition to the componentsdiscussed with respect to FIG. 1 , the ventilator 100 includes aventilation assembly 190, a user interface 200, an oxygen assembly 210,a control system 220, and conventional monitoring and alarm systems 221.Because those of ordinary skill in the art are familiar withconventional monitoring and alarm systems 221, they will not bedescribed in detail herein.

The control system 220 receives input information 196 (e.g., settings,parameter values, and the like) from the user interface 200, andprovides output information 198 (e.g., performance information, statusinformation, and the like) to the user interface 200. The user interface200 is configured to receive input from a user (e.g., a caregiver, aclinician, and the like associated with the patient 102 depicted in FIG.1 ) and provide that input to the control system 220 in the inputinformation 196. The user interface 200 is also configured to displaythe output information 198 to the user.

As mentioned above, referring to FIG. 1 , the patient circuit 110 mayinclude the optional port(s) 111 configured to allow one or morepressure signals 109 to flow between the optional multi-lumen tubeconnection 103 and the patient circuit 110. Referring to FIG. 3 , theoptional multi-lumen tube connection 103 is configured to provide thepressure signal(s) 109 to the ventilation assembly 190.

As will be explained below, the ventilation assembly 190 may receive oneor more control signals 192 from the control system 220, and theventilation assembly 190 may provide one or more data signals 194 to thecontrol system 220. Similarly, the oxygen assembly 210 may receive oneor more control signals 260 from the control system 220, and the oxygenassembly 210 may provide one or more data signals 262 to the controlsystem 220. The control signals 192 and 260 and the data signals 194 and262 may be used by the control system 220 to monitor and/or controlinternal operations of the ventilator 100.

Ventilation Assembly

FIGS. 5A and 5B are schematic diagrams illustrating some exemplarycomponents of the ventilation assembly 190. FIG. 5E is a block diagramillustrating exemplary components of the control system 220, the controlsignal(s) 192 sent by the control system 220 to exemplary components ofthe ventilation assembly 190, and the data signals 194 received by thecontrol system 220 from exemplary components of the ventilation assembly190.

Referring to FIGS. 5A and 5B, the ventilation assembly 190 includes acough assist valve 204, an accumulator 202, an internal flow transducer212, a blower 222, an airway pressure transducer 224, an airway flowtransducer module 225, an exhalation control assembly 226, an oxygensensor 227, an ambient pressure transducer 228, an inlet silencer 229,and an internal bacteria filter 230.

The cough assist valve 204 is connected to the accumulator 202 by aconduit or flow line 214. For ease of illustration, a portion of theflow line 214 between the accumulator 202 and the internal flowtransducer 212 has been omitted from FIGS. 5A and 5B.

The cough assist valve 204 is connected to the outlet port 166 by aconduit or flow line 215. For ease of illustration, a portion of theflow line 215 between the cough assist valve 204 and the outlet port 166has been omitted from FIGS. 5A and 5B.

The cough assist valve 204 is connected to the main ventilatorconnection 104 by a conduit or flow line 273. For ease of illustration,a portion of the flow line 273 between the cough assist valve 204 andthe internal bacteria filter 230 has been omitted from FIGS. 5A and 5B.

FIG. 5A depicts the cough assist valve 204 in a first configuration andFIG. 5B depicts the cough assist valve 204 in a second configuration.Referring to FIG. 5A, in the first configuration, the cough assist valve204 receives a gas 252 from the accumulator 202 (via the flow line 214),and outputs the gas 252 to the main ventilator connection 104 (via theflow line 273). During normal breathing and ventilation, the coughassist valve 204 remains in the first configuration. When cough assistfunctionality (described below) is used to perform a cough assistmaneuver, the cough assist valve 204 is in the first configurationduring the insufflation phase of a cough and the cough assist valve 204is in the second configuration during the exsufflation phase of thecough. Referring to FIG. 5B, in the second configuration, the coughassist valve 204 receives exsufflation gases 253 via the flow line 273,and outputs the exsufflation gases 253 (as the exhaust 167) to theoutlet port 166 via the flow line 215.

FIG. 5C is an enlarged schematic diagram of the cough assist valve 204in the first configuration. FIG. 5C illustrates the gas 252 flowingthrough both the blower 222 and the cough assist valve 204 during theinspiratory phase of a breath or the insufflation phase of a coughassist maneuver performed by the ventilator 100 (see FIGS. 1 and 4 ).

FIG. 5D is an enlarged schematic diagram of the cough assist valve 204in the second configuration. FIG. 5D illustrates the exsufflation gases253 flowing through both the blower 222 and the cough assist valve 204during an exsufflation phase of a cough assist maneuver performed by theventilator 100 (see FIGS. 1 and 4 ). For ease of illustration, ports275A-275C (see FIGS. 5A and 5B) have been omitted from FIGS. 5C and 5D.

Referring to FIGS. 5C and 5D, the cough assist valve 204 has avalve-to-blower outlet 1002, a blower-to-valve inlet 1004, an air intake1006, an exhaust outlet 1008, and an aperture 1010. The aperture 1010 isconnected to the main ventilator connection 104 by the flow line 273. Asshown in FIG. 5C, when the cough assist valve 204 is in the firstconfiguration, the air intake 1006 is in fluid communication with thevalve-to-blower outlet 1002, and the blower-to-valve inlet 1004 is influid communication with the aperture 1010. Further, the exhaust outlet1008 is closed, and both the valve-to-blower outlet 1002 and the airintake 1006 are out of fluid communication with the aperture 1010 exceptvia the blower 222. Thus, the gas 252 may flow into the air intake 1006,through a portion of the cough assist valve 204 and out of thevalve-to-blower outlet 1002, and into the blower 222. The gas 252exiting the blower 222 flows into the blower-to-valve inlet 1004,through a portion of the cough assist valve 204, and exits the coughassist valve 204 through the aperture 1010. The aperture 1010 isconnected to the flow line 273, which conducts the gas 252 (see FIG. 5A)to the main ventilator connection 104.

As shown in FIG. 5D, when the cough assist valve 204 in the secondconfiguration, the air intake 1006 is closed, and both theblower-to-valve inlet 1004 and the exhaust outlet 1008 are out of fluidcommunication with the aperture 1010 except via the blower 222. Further,the aperture 1010 is in fluid communication with the valve-to-bloweroutlet 1002, and the blower-to-valve inlet 1004 is in fluidcommunication with the exhaust outlet 1008. Thus, the exsufflation gases253 flow into the aperture 1010, through a portion of the cough assistvalve 204 and out the valve-to-blower outlet 1002, and into the blower222. The exsufflation gases 253 exiting the blower 222 flow into theblower-to-valve inlet 1004, through a portion of the cough assist valve204, and exit the cough assist valve 204 through the exhaust outlet1008. The exhaust outlet 1008 is connected to the flow line 215 (seeFIGS. 5A and 5B), which conducts the exsufflation gases 253 (as theexhaust 167 illustrated in FIGS. 5A and 5B) to the outlet port 166.

FIGS. 17A and 17B are perspective views of the cough assist valve 204.FIGS. 18A and 18B are cross-sectional views of the cough assist valve204. FIG. 18A depicts the cough assist valve 204 in the firstconfiguration, and FIG. 18B depicts the cough assist valve 204 in thesecond configuration.

Referring to FIG. 17A, the cough assist valve 204 includes a generallycylindrically shaped housing 1020. In the embodiment illustrated, theair intake 1006 is formed in a first open end 1022 of the housing 1020and the exhaust outlet 1008 (see FIG. 17B) is located at a second openend 1024 of the housing 1020 with the second open end 1024 beingopposite the first open end 1022. The valve-to-blower outlet 1002, theblower-to-valve inlet 1004, and the aperture 1010 (see FIG. 17B) areformed in a sidewall 1026 of the housing 1020 extending between thefirst and second open ends 1022 and 1024 thereof.

A first end cap assembly 1032 may be coupled to the first open end 1022,and a second end cap assembly 1034 may be coupled to the second open end1024. The first and second end cap assemblies 1032 and 1034 aresubstantially identical to one another. Referring to FIG. 19A, each ofthe first and second end cap assemblies 1032 and 1034 (see FIGS. 17A,17B, 18A and 18B) includes a magnet 1040, a retaining member 1042, asealing member 1044 (e.g., an O-ring), and a seat member 1046. Thesealing member 1044 is positioned between the seat member 1046 and theretaining member 1042. Each of the first and second end cap assemblies1032 and 1034 may be coupled to the housing 1020 by one or more tabs1048 and one or more fasteners 1049. Referring to FIGS. 17A and 17B, inthe embodiment illustrated, the housing 1020 includes an outwardlyextending mounting portion 1050 at each of the first and second openends 1022 and 1024 of the housing 1020, each configured to receive oneof the each fasteners 1049.

In the embodiment illustrated, the magnet 1040 is generallycylindrically or disk shaped. However, this is not a requirement.

Referring to FIG. 19A, the retaining member 1042 has a ring-shaped baseportion 1052 defining an opening 1053. A sidewall 1054 extends inwardlyfrom the base portion 1052 toward the seat member 1046. Each tab 1048 isconfigured to abut the base portion 1052 and avoid obstructing theopening 1053. Thus, gas (e.g., the gas 252 or the exsufflation gases253) may pass through the opening 1053 unobstructed by the tab(s) 1048.

Referring to FIGS. 19B and 19C, the seat member 1046 has a ring-shapedperipheral portion 1056 defining an opening 1058 therewithin. A centralmagnet receiving portion 1060 is supported within the opening 1058 byradially extending support arms 1061-1063 connected to the peripheralportion 1056. Together the magnet receiving portion 1060 and the supportarms 1061, 1062 and 1063 which only partially obstruct or occlude theopening 1058. Thus, gas (e.g., the gas 252 or the exsufflation gases253) may pass through the opening 1058 around the magnet receivingportion 1060 and the support arms 1061, 1062 and 1063.

The seat member 1046 has an inwardly facing side 1070 (see FIG. 19C)opposite an outwardly facing side 1071 (see FIG. 19B). Referring to FIG.19C, the peripheral portion 1056 along the inwardly facing side 1070 isconfigured to be at least partially received inside one of the first andsecond open ends 1022 and 1024 (see FIGS. 17A-18B) of the housing 1020.Along the inwardly facing side 1070, the peripheral portion 1056 has aninwardly extending annular projection 1072 positioned adjacent theopening 1058. In the embodiment illustrated, the peripheral portion 1056has a longitudinally inwardly facing, annularly extending helical rampportion 1074 along the inwardly facing side 1070. As will be describedin greater detail below, the ramp portion 1074 is used to adjustablylongitudinally position the seat members 1046 of the first and secondend cap assemblies 1032 and 1034 within the housing 1020.

Referring to FIG. 19B, in the embodiment illustrated, the peripheralportion 1056 has an annular shaped recessed portion 1076 along theoutwardly facing side 1071. The recessed portion 1076 is configured toreceive the sealing member 1044 and at least a free end portion of theinwardly extending sidewall 1054 of the retaining member 1042 with thesealing member 1044 sandwiched between the seat member 1046 and theretaining member 1042.

At the outwardly facing side 1071, the magnet receiving portion 1060 isconfigured to receive the magnet 1040 (see FIG. 19A). In the embodimentillustrated, the magnet receiving portion 1060 has been implemented asan open ended cylinder. However, this is not a requirement. Along theinwardly facing side 1070 (see FIG. 19C), the magnet receiving portion1060 has an inner stop wall 1066 configured to prevent the magnet 1040from passing through the central magnet receiving portion 1060 into thehousing 1020. By way of a non-limiting example, the magnet 1040 (seeFIG. 19A) may be retained inside the magnet receiving portion 1060 byfriction or an adhesive.

Referring to FIG. 23A, the first open end 1022 of the housing 1020 has alongitudinally outward facing, annularly extending first inside helicalramp portion 1092 configured to mate with the helical ramp portion 1074(see FIG. 19C) of the first end cap assembly 1032 (see FIGS. 17A, 18Aand 18B). A ring-shaped inner seat member 1096 is positioned inside thehousing 1020 at a circumferentially extending, radially projecting,inner wall 1185 near but inward of the first open end 1022. The innerseat member 1096 has a longitudinally outwardly extending annularprojection 1097 substantially similar to the inwardly annular projection1072 (see FIG. 19C).

Referring to FIG. 19C, the annular projection 1072 formed on theinwardly facing side 1070 of the seat member 1046 of the first end capassembly 1032 functions as a first seat “S1” (see FIGS. 18A and 18B).The annular projection 1097 within the housing 1020 at the first openend 1022 functions as a second seat “S2” (see FIGS. 18A and 18B). As maybe seen in FIGS. 18A and 18B, the second seat “S2” is positionedlongitudinally inward from the first cap assembly 1032. The first andsecond seats “S1” and “S2” extend toward and face one another.

Referring to FIG. 23B, the second open end 1024 of the housing 1020 hasa longitudinally outward facing, annularly extending second insidehelical ramp portion 1094 configured to mate with the helical rampportion 1074 (see FIG. 19C) of the second end cap assembly 1034 (seeFIGS. 17B, 18A and 18B). The housing 1020 has circumferentiallyextending, radially inwardly projecting, inner wall 1100 near but inwardof the second open end 1024. The inner wall 1100 has a longitudinallyoutwardly extending annular projection 1102 substantially similar to theannular projection 1072 (see FIG. 19C). The annular projection 1102within the housing 1020 at the second open end 1024 functions as a thirdseat “S3” (see FIGS. 18A and 18B). As shown in FIGS. 18A and 18B, thethird seat “S3” is positioned longitudinally inward from the second endcap assembly 1034. The annular projection 1072 (see FIG. 19C) of theseat member 1046 (see FIG. 19C) of the second end cap assembly 1034functions as a fourth seat “S4.” The third and fourth seats “S3” and“S4” extend toward and face one another.

The first seat “S1” is positioned adjacent to the air intake 1006, andthe fourth seat “S4” is positioned adjacent to the exhaust outlet 1008.The valve-to-blower outlet 1002 is positioned between the first seat“S1” and the second seat “S2” inside the housing 1020. Similarly, theblower-to-valve inlet 1004 is positioned between the third seat “S3” andthe fourth seat “S4” formed in the housing 1020.

The cough assist valve 204 includes first and second poppet valveassemblies 1112 and 1114 connected together by a shaft 1116 so as tomove together in unison. The cough assist valve 204 has first, secondand third interior chambers, as will be described below. The firstpoppet valve assembly 1112 is located in the first chamber between thefirst and second seats “S1” and “S2,” and moves longitudinally betweenthe first and second seats “S1” and “S2,” and the second poppet valveassembly 1114 is located in the third chamber between the third andfourth seats “S3” and “S4,” and moves longitudinally between the thirdand fourth seats “S3” and “S4.” The second chamber is located betweenthe second and third seats “S2” and “S3,” respectively, and hence islocated between the first and third chambers. The second seat “S2”defines a first aperture through which the first and second chambers arein fluid communication and the first poppet valve assembly 1112 controlsflow through the first aperture, and the third seat “S3” defines asecond aperture through which the second and third chambers are in fluidcommunication and the second poppet valve assembly 1114 controls flowthrough the second aperture. As shown in FIG. 18A, when the first poppetvalve assembly 1112 is pressed against the second seat “S2,” the coughassist valve 204 is in the first configuration illustrated in FIGS. 5Aand 5C. In the first configuration, the first poppet valve assembly 1112permits the flow of gas 252 from the accumulator 202 to flow through theair intake 1006 into the first chamber and then to the valve-to-bloweroutlet 1002, and enter the blower 222, while blocking flow of the gas252 directly to the aperture 1010, thus sealing the aperture 1010 fromboth the air intake 1006 and the valve-to-blower outlet 1002. At thesame time, the second poppet valve assembly 1114 is pressed against thefourth seat “S4,” so that the second poppet valve assembly 1114 closesthe exhaust outlet 1008 and directs the flow of the gas 252 into thethird chamber and then through the second aperture into the secondchamber for exit through the aperture 1010 to the main ventilatorconnection 104. In this configuration, the gas 252 from the accumulator202 entering the air intake 1006 is directed to the blower 222 throughthe valve-to-blower outlet 1002. The gas 252 is then blown by the blower222 into the blower-to-valve inlet 1004 and exit the cough assist valve204 through the aperture 1010 to the main ventilator connection 104.

As shown in FIG. 18B, when the first poppet valve assembly 1112 ispressed against the first seat “S1,” the cough assist valve 204 is inthe second configuration illustrated in FIGS. 5B and 5D. In the secondconfiguration, the first poppet valve assembly 1112 permits the flow ofexsufflation gases 253 from the main ventilator connection 104 to flowthrough the aperture 1010 into the second chamber and then through thefirst aperture into the first chamber for exit through thevalve-to-blower outlet 1002, and entry to the blower 222, while blockingflow of the exsufflation gases to the air intake 1006 and alsopreventing gas 252 from the accumulator 202 reaching the valve-to-bloweroutlet 1002. At the same time, the second poppet valve assembly 1114 ispressed against the third seat “S3,” so that the second poppet valveassembly 1114 opens the exhaust outlet 1008 and blocks the flow of theexsufflation gases 253 through the second aperture into the secondchamber and to the aperture 1010. In this configuration, theexsufflation gases 253 from the main ventilator connection 104 enteringthe aperture 1010, pass through the first chamber and are directed tothe blower 222 through the valve-to-blower outlet 1002. The exsufflationgases 253 are then blown by the blower 222 into the blower-to-valveinlet 1004 and into the third chamber and exit the cough assist valve204 through the exhaust outlet 1008 to the outlet port 166.

The first and second poppet valve assemblies 1112 and 1114 are coupledto opposite ends of the shaft 1116 to move therewith as a unit inunison. Referring to FIG. 22 , in the embodiment illustrated, a guidemember 1120 (e.g., a pin, dowel, and the like) extends laterallyoutwardly from the shaft 1116. The shaft 1116 may include one or morecircumferentially extending grooves 1122 and 1124 each configured toreceive a different retaining ring 1126. The shaft 1116 has a first endportion 1132 opposite a second end portion 1134. Longitudinal channels1136 and 1138 extend inwardly into the shaft at the first and second endportions 1132 and 1134, respectively. Each of the channels 1136 and 1138is configured to receive a fastener 1140 (see FIG. 21 ).

The shaft 1116 is configured to move longitudinally within the housing1020 between a first position (see FIG. 18A) whereat the cough assistvalve 204 is in the first configuration and a second position (see FIG.18B) whereat the cough assist valve 204 is in the second configuration.Referring to FIGS. 18A and 18B, as the shaft 1116 moves, the firstpoppet valve assembly 1112 moves between the first and second seats “S1”and “S2,” and the second poppet valve assembly 1114 moves between thethird and fourth seats “S3” and “S4.” When the shaft 1116 is in thefirst position (see FIG. 18A), the first poppet valve assembly 1112 isin sealing position against the first seat “S1,” and the second poppetvalve assembly 1114 is in sealing position against the third seat “S3.”When the shaft 1116 is in the second position (see FIG. 18B), the firstpoppet valve assembly 1112 is in sealing position against the secondseat “S2,” and the second poppet valve assembly 1114 is in sealingposition against the fourth seat “S4.”

The ramp portion 1074 of seat member 1046 of the first end cap assembly1032 is in sliding engagement with the ramp portion 1092 within thefirst open end 1022 of the housing 1020 such that rotation of the seatmember 1046 causes adjustable longitudinal movement relative to thehousing 1020 to precisely adjust the position of the first seat “S1” ofthe seat member 1046, during assembly and calibration, with respect tothe first poppet valve assembly 1112 to achieve the desired seal andseating therebetween. Similarly, the ramp portion 1074 of seat member1046 of the second end cap assembly 1034 is in sliding engagement withthe ramp portion 1094 within the second open end 1024 of the housing1020 such that rotation of the seat member 1046 causes adjustablelongitudinal movement relative to the housing 1020 to precisely adjustthe position of the fourth seat “S4” of the seat member 1046, duringassembly and calibration, with respect to the second poppet valveassembly 1114 to achieve the desired seal and seating therebetween.

The first and second poppet valve assemblies 1112 and 1114 aresubstantially identical to one another. Referring to FIG. 21 , each ofthe first and second poppet valve assemblies 1112 and 1114 includes thefastener 1140, a ferromagnetic member 1144, a first sealing member 1146(e.g., an O-ring), a disk shaped poppet member 1148, a second sealingmember 1150 (e.g., an O-ring), and an optional washer 1152.

The fastener 1140 of the first poppet valve assembly 1112 fastens theother components (namely, the ferromagnetic member 1144, the firstsealing member 1146, the poppet member 1148, the second sealing member1150, and optionally, the washer 1152) of the first poppet valveassembly 1112 to the first end portion 1132 of the shaft 1116.Similarly, the fastener 1140 of the second poppet valve assembly 1114fastens the other components of the second poppet valve assembly 1114 tothe second end portion 1134 of the shaft 1116. The first and secondsealing members 1146 and 1150 of each of the first and second poppetvalve assemblies 1112 and 1114 serve to both seal the poppet valveassemblies to the end portion of the shaft 1116 and provide a flexiblecoupling between the shaft and the poppet members 1148 of the poppetvalve assemblies.

Referring to FIG. 18A, the magnet 1040 of the first end cap assembly1032 attracts the ferromagnetic member 1144 of the first poppet valveassembly 1112 and when in proximity therewith maintains the shaft 1116in the first position after the shaft has been moved to the firstposition and holds the first poppet valve assembly 1112 in place at thefirst seat “S1” of the first end cap assembly 1032. Similarly, referringto FIG. 18B, the magnet 1040 of the second end cap assembly 1034attracts the ferromagnetic member 1144 of the second poppet valveassembly 1114 and when in proximity therewith maintains the shaft 1116in the second position after the shaft has been moved to the secondposition and holds the second poppet valve assembly 1114 in place at thefourth seat “S4” of the second end cap assembly 1034. The ferromagneticmembers 1144 holds the poppet valve assemblies 1112 and 1114 in placewith respect to the first and fourth seats “S1” and “S4,” respectively,even when power is not being applied to the actuator used to move thepoppet valve assemblies.

Referring to FIG. 20 , the cough assist valve 204 includes an actuator1170 configured to selectively move the shaft 1116 between the firstposition (see FIG. 18A) and the second position (see FIG. 18B) alonglongitudinal directions identified by double headed arrow 1172. In theembodiment illustrated, the actuator 1170 is a linear actuatorimplemented using a voice coil that includes a movable coil subassembly1174 and a stationary magnet subassembly 1176. The shaft 1116 is coupledto the movable coil subassembly 1174 and moves therewith as a unit.Referring to FIGS. 18A and 18B, the stationary magnet subassembly 1176is coupled to an actuator mounting portion 1190 of the housing 1020(e.g., by one or more fasteners 1178).

Referring to FIG. 18A, the movable coil subassembly 1174 is connected byone or more wires 1059 to a printed circuit board (“PCB”) 1064 mountedto the outside of the housing 1020. In the embodiment illustrated, thewire(s) 1059 provide power to the movable coil subassembly 1174. Thehousing 1020 includes one or more apertures 1065 (see FIG. 24A) throughwhich the wire(s) 1059 may pass. The PCB 1064 is connected to thecontrol system 220 (see FIG. 5E) by one or more wires (not shown). Theactuator 1170 is configured to receive a control signal 1180 (see FIG.5E) from the control system 220 (via the PCB 1064 and the wire(s) 1059)and move in accordance with one or more instructions in the controlsignal 1180. The PCB 1064 serves as a connector and passes the controlsignal 1180 to the movable coil subassembly 1174.

The control signal 1180 (see FIG. 5E) selectively powers the movablecoil subassembly 1174 to move toward either the first end cap assembly1032 or the second end cap assembly 1034. When the movable coilsubassembly 1174 moves toward the first end cap assembly 1032, themovable coil subassembly 1174 moves the shaft 1116 toward the firstposition. Referring to FIG. 18A, after the shaft 1116 has moved to thefirst position, the movable coil subassembly 1174 is powered down andthe magnet 1040 of the first end cap assembly 1032 (which, as describedabove is attracted to at least a portion of the first poppet valveassembly 1112) maintains the shaft 1116 in the first position. On theother hand, when the movable coil subassembly 1174 moves toward thesecond end cap assembly 1034, the movable coil subassembly 1174 movesthe shaft 1116 toward the second position. Referring to FIG. 18B, afterthe shaft 1116 has moved to the second position, the movable coilsubassembly 1174 is powered down and the magnet 1040 of the second endcap assembly 1034 (which, as described above is attracted to at least aportion of the second poppet valve assembly 1114) maintains the shaft1116 in the second position. Thus, additional power is not needed tomaintain the shaft 1116 in either the first position or the secondposition, which helps extend battery life in embodiments powered by oneor more batteries.

Referring to FIG. 24B, the housing 1020 (see FIGS. 18A and 18B) includesa first internal support 1184 spaced inwardly from the first open end1022. In the embodiment illustrated, the first internal support 1184extends radially inward from the circumferentially inwardly extendinginner wall 1185. The first internal support 1184 has a longitudinallyextending channel 1186 formed therein. Referring to FIGS. 18A and 18B,the channel 1186 (see FIG. 24B) is configured to allow the shaft 1116 topass fully therethrough to position the first poppet valve assembly 1112between the first internal support 1184 and the first end cap assembly1032. As may be viewed in FIG. 23A, the channel 1186 opens alongside theinner seat member 1096, and as shown in FIGS. 18A and 18B, positions thefirst poppet valve assembly 1112 between the first and second seats “S1”and “S2.” A portion of the shaft 1116 near the first end portion 1132including the guide member 1120 (see FIG. 22 ) is positioned inside thechannel 1186 (see FIG. 24B) and reciprocates therein. Referring to FIG.24A, an open-ended, longitudinally extending guide groove 1188 is formedin the first internal support 1184 alongside the channel 1186. The guidemember 1120 (see FIG. 22 ) is positioned in and moves within the guidegroove 1188. (This prevents rotation of the poppet assembly, which coulddamage the wires.)

The first internal support 1184 has the actuator mounting portion 1190which optionally includes one or more through-holes configured toreceive the fastener(s) 1178 (see FIGS. 18A and 18B). The stationarymagnet subassembly 1176 (see FIGS. 18A and 18B) is coupled to theactuator mounting portion 1190 which anchors the stationary magnetsubassembly to the housing 1020 (see FIGS. 18A and 18B). In theembodiment illustrated, the actuator mounting portion 1190 includes aninwardly extending peripheral sidewall 1192 configured to extend arounda portion of the stationary magnet subassembly 1176.

Referring to FIG. 25 , the housing 1020 (see FIGS. 18A and 18B) includesa second internal support 1194 spaced inwardly from the second open end1024. In the embodiment illustrated, the second internal support 1194extends radially inward from the inner wall 1100. The second internalsupport 1194 has a through-hole 1196 formed therein. Referring to FIGS.18A and 18B, the through-hole 1196 (see FIG. 25 ) is configured to allowthe shaft 1116 to pass therethrough to position the second poppet valveassembly 1114 between the second internal support 1194 and the secondend cap assembly 1034. As may be viewed in FIG. 25 , the through-hole1196 opens alongside the annular projection 1102, and as shown in FIGS.18A and 18B, positions the second poppet valve assembly 1114 between thethird and fourth seats “S3” and “S4.”

Referring to FIGS. 17A, 17B, 18A, 18B, 23A, and 23B, in the embodimentillustrated, the housing 1020 includes an intake body portion 1198coupled to an exhaust body portion 1199. The valve-to-blower outlet1002, the air intake 1006, the aperture 1010, the first open end 1022,and the first internal support 1184 are formed in the intake bodyportion 1198. The blower-to-valve inlet 1004, the exhaust outlet 1008,the second open end 1024, and the second internal support 1194 areformed in the exhaust body portion 1199.

In the embodiment illustrated, the cough assist valve 204 includes theports 275A, 275B and 275C (described below) formed in the housing 1020.The ports 275A and 275B may be formed in the exhaust body portion 1199,and the port 275C may be formed in the intake body portion 1198.However, this is not a requirement. Optionally, the cough assist valve204 includes a port 275D (see FIGS. 17B and 23A) configured to beconnected to a redundant airway pressure transducer (not shown).

FIGS. 34A and 34B are cross-sectional views of an alternate embodimentof a cough assist valve 2000 that may be used in the ventilationassembly 190 (see FIGS. 4 and 5A), instead of the cough assist valve 204(see FIGS. 5A-5D and 17A-18B). Referring to FIGS. 5A and 5B, like thecough assist valve 204, the cough assist valve 2000 (see FIGS. 34A and34B) is configured to be connected to the accumulator 202 by the flowline 214, to the outlet port 166 by the flow line 215, and to the mainventilator connection 104 by the flow line 273.

FIG. 34A depicts the cough assist valve 2000 in a first configurationand FIG. 34B depicts the cough assist valve 2000 in a secondconfiguration. The first and second configurations of the cough assistvalve 2000 correspond and provide identical functionality to the firstand second configurations, respectively, of the cough assist valve 204(see FIGS. 5A-5D and 17A-18B). Thus, during normal breathing andventilation, the cough assist valve 2000 remains in the firstconfiguration. When cough assist functionality (described below) is usedto perform a cough assist maneuver, the cough assist valve 2000 is inthe first configuration during the insufflation phase of a cough and thecough assist valve 2000 is in the second configuration during theexsufflation phase of the cough.

Referring to FIGS. 34A, 34B, 18A, and 18B, the cough assist valve 2000has a valve-to-blower outlet 2002, a blower-to-valve inlet 2004, an airintake 2006, an exhaust outlet 2008, and an aperture 2010 substantiallyidentical to the valve-to-blower outlet 1002, the blower-to-valve inlet1004, the air intake 1006, the exhaust outlet 1008, and the aperture1010, respectively, of the cough assist valve 204. The valve-to-bloweroutlet 2002 and the blower-to-valve inlet 2004 are each connected to theblower 222. The air intake 2006 is connected to the accumulator 202 bythe flow line 214. The exhaust outlet 2008 is connected to the outletport 166 by the flow line 215. The aperture 2010 is connected to themain ventilator connection 104 by the flow line 273. The cough assistvalve 2000 has seats “S1′” to “S4′” that are substantially identical tothe seats “S1” to “S4,” respectively, of the cough assist valve 204.

Referring to FIGS. 34A and 34B, the cough assist valve 2000 includes agenerally cylindrically shaped housing 2020. The air intake 2006 isformed in a first open end 2022 of the housing 2020 and the exhaustoutlet 2008 is formed at a second open end 2024 of the housing 2020. Thevalve-to-blower outlet 2002, the blower-to-valve inlet 2004, and theaperture 2010 are formed in a sidewall 2026 of the housing 2020extending between the first and second open ends 2022 and 2024 thereof.

First and second end cap assemblies 2032 and 2034 may be coupled to thefirst and second open ends 2022 and 2024, respectively. The first andsecond end cap assemblies 2032 and 2034 are substantially identical toone another. Referring to FIG. 35 , each of the first and second end capassemblies 2032 and 2034 (see FIGS. 34A and 34B) includes a retainingmember 2042, a sealing member 2044 (e.g., an O-ring), and a seat member2046. Referring to FIGS. 34A and 34B, each of the first and second endcap assemblies 2032 and 2034 may be coupled to the housing 2020 by oneor more fasteners 2049. In the embodiment illustrated, the housing 2020includes one or more outwardly extending mounting portions 2050 at eachof the first and second open ends 2022 and 2024 of the housing 2020 eachconfigured to receive one of the fasteners 2049.

Referring to FIG. 35 , the seat member 2046 has a ring-shaped peripheralportion 2056 defining an opening 2058. The seat member 2046 has aninwardly facing side 2070 opposite an outwardly facing side 2071. Alongthe inwardly facing side 2070, the seat member 2046 has an inwardlyextending annular projection 2072 positioned adjacent the opening 2058.In the embodiment illustrated, the peripheral portion 2056 has anoutside threaded portion 2074 along the inwardly facing side 2070 and anannular shaped recessed portion 2076 along the outwardly facing side2071. The recessed portion 2076 is configured to receive the sealingmember 2044 and at least a free end portion of an inwardly extendingsidewall 2054 of the retaining member 2042 with the sealing member 2044sandwiched between the seat member 2046 and the retaining member 2042.

The first and second end cap assemblies 2032 and 2034 (see FIGS. 34A and34B) do not include the tabs 1048 (see FIG. 19A). Instead, the retainingmember 2042 of the first end cap assembly 2032 (see FIGS. 34A and 34B)includes an outwardly extending mounting portion 2057 for each of theoutwardly extending mounting portions 2050 (see FIGS. 34A, 34B, and 37 )located at the first open end 2022 (see FIGS. 34A and 34B) of thehousing 2020. Similarly, each mounting portion 2057 of the retainingmember 2042 of the second end cap assembly 2034 (see FIGS. 34A and 34B)corresponds to one of the outwardly extending mounting portions 2050(see FIGS. 34A, 34B, and 38 ) located at the second open end 2024 of thehousing 2020. Each mounting portion 2057 is configured to receive one ofthe fasteners 2049 and be fastened thereby to the mounting portion 2050(see FIGS. 34A, 34B, and 38 ) that corresponds to the mounting portion2057.

Referring to FIG. 37 , the first open end 2022 of the housing 2020 (seeFIGS. 34A and 34B) has a first inside threaded portion 2092 configuredto mate with the outside threaded portion 2074 (see FIG. 35 ) of thefirst end cap assembly 2032 (see FIGS. 34A and 34B). The housing 2020(see FIGS. 34A and 34B) has circumferentially extending, radiallyinwardly projecting, inner wall 2095 near but inward of the first openend 2022. The inner wall 2095 has a longitudinally outwardly extendingannular projection 2097 substantially similar to the annular projection2072 (see FIG. 35 ).

Referring to FIG. 35 , the annular projection 2072 of the seat member2046 of the first end cap assembly 2032 (see FIGS. 34A and 34B)functions as the first seat “S1′” (see FIGS. 34A and 34B). Referring toFIG. 37 , the annular projection 2097 inside the first open end 2022 ofthe housing 2020 functions as the second seat “S2′” (see FIGS. 34A and34B). As may be seen in FIGS. 34A and 34B, the second seat “S2′” ispositioned longitudinally inward from the first cap assembly 2032. Thefirst and second seats “S1′” and “S2′” extend toward and face oneanother.

Referring to FIG. 38 , the second open end 2024 of the housing 2020 (seeFIGS. 34A and 34B) has a second inside threaded portion 2094 configuredto mate with the outside threaded portion 2074 (see FIG. 35 ) of thesecond end cap assembly 2034 (see FIGS. 34A and 34B). The housing 2020(see FIGS. 34A and 34B) has circumferentially extending, radiallyinwardly projecting, inner wall 2100 near but inward of the second openend 2024. The inner wall 2100 has a longitudinally outwardly extendingannular projection 2102 substantially similar to the annular projection2072 (see FIG. 35 ). Referring to FIGS. 34A and 34B, the annularprojection 2102 (see FIG. 38 ) within the housing 2020 at the secondopen end 2024 functions as the third seat “S3′.” The third seat “S3′” ispositioned longitudinally inward from the second end cap assembly 2034.The annular projection 2072 (see FIG. 35 ) of the seat member 2046 (seeFIG. 35 ) of the second end cap assembly 2034 functions as a fourth seat“S4′.” The third and fourth seats “S3′” and “S4′” extend toward and faceone another.

Referring to FIGS. 34A and 34B, the cough assist valve 2000 includesfirst and second poppet valve assemblies 2112 and 2114 connectedtogether by a shaft 2116 so as to move together in unison. The firstpoppet valve assembly 2112 is located and moves longitudinally betweenthe first and second seats “S1′” and “S2′,” and the second poppet valveassembly 2114 is located and moves longitudinally between the third andfourth seats “S3′” and “S4′.”

Referring to FIGS. 34A and 34B, the shaft 2116 is configured to movelongitudinally within the housing 2020 between a first position (seeFIG. 34A) whereat the cough assist valve 2000 is in the firstconfiguration and a second position (see FIG. 34B) whereat the coughassist valve 2000 is in the second configuration. As the shaft 2116moves, the first poppet valve assembly 2112 moves between the first andsecond seats “S1′” and “S2′,” and the second poppet valve assembly 2114moves between the third and fourth seats “S3′” and “S4′.” When the shaft2116 is in the first position (see FIG. 34A), the first poppet valveassembly 2112 is in sealing position against the first seat “S1′,” andthe second poppet valve assembly 2114 is in sealing position against thethird seat “S3′.” When the shaft 2116 is in the second position (seeFIG. 34B), the first poppet valve assembly 2112 is in sealing positionagainst the second seat “S2′,” and the second poppet valve assembly 2114is in sealing position against the fourth seat “S4”.

Referring to FIG. 34A, a longitudinal channel 2136 extends inwardly intothe shaft 2116 at each of its ends. Referring to FIG. 36 , each of thechannels 2136 (see FIG. 34A) is configured to receive a fastener 2140(see FIG. 21 ). The first and second poppet valve assemblies 2112 and2114 are substantially identical to one another. Referring to FIG. 36 ,each of the first and second poppet valve assemblies 2112 and 2114includes the fastener 2140, an optional first washer 2146, a disk shapedpoppet member 2148, and an optional second washer 2152. While notvisible in FIG. 36 , the first and second poppet valve assemblies 2112and 2114 each include first and second sealing members 1146 and 1150,much as shown in FIG. 21 , which serve to both seal the poppet valveassemblies to the end portion of the shaft 2116 and provide a flexiblecoupling between the shaft and the poppet valve members 2148 of thepoppet valve assemblies. The fastener 2140 of the first poppet valveassembly 2112 fastens the other components (namely, the optional firstwasher 2146, the disk shaped poppet member 2148, and the optional secondwasher 2152) of the first poppet valve assembly 2112 to one of the endsof the shaft 2116. Similarly, the fastener 2140 of the second poppetvalve assembly 2114 fastens the other components of the second poppetvalve assembly 2114 to the other end of the shaft 2116.

Referring to FIGS. 34A and 34B, the cough assist valve 2000 includes anactuator 2170 configured to selectively move the shaft 2116 between thefirst position (see FIG. 34A) and the second position (see FIG. 34B)along longitudinal directions identified by double headed arrow 2172(see FIG. 36 ). In the embodiment illustrated, the actuator 2170 is alinear actuator that includes a stationary coil subassembly 2174 and amovable magnet subassembly 2176. The shaft 2116 is coupled to themovable magnet subassembly 2176 and moves therewith as a unit.

Referring to FIGS. 34A and 34B, the stationary coil subassembly 2174includes a coil 2177 housed inside an outer housing 2179. The outerhousing 2179 is coupled to an actuator mounting portion 2190 of thehousing 2020 (e.g., by one or more fasteners 2178). The outer housing2179 is constructed from a magnetic material. The coil 2177 is connectedby one or more wires 2062 to a printed circuit board (“PCB”) 2064mounted to the outside of the housing 2020. In the embodimentillustrated, the wire(s) 2062 provide power to the coil 2177. The outerhousing 2179 and the housing 2020 each include one or more aperturesthrough which the wire(s) 2062 may pass. The PCB 2064 is connected tothe control system 220 (see FIG. 5E) by one or more wires (not shown).The actuator 2170 is configured to receive the control signal 1180 (seeFIG. 5E) from the control system 220 (via the PCB 2064 and the wire(s)2062) and move in accordance with one or more instructions in thecontrol signal 1180. The PCB 2064 serves as a connector and passes thecontrol signal 1180 to the coil 2177.

Referring to FIG. 36 , the movable magnet subassembly 2176 has a mainmagnet 2150 with a first end 2151 opposite a second end 2153. A firstlatch magnet 2156 is mounted to the first end 2151 and a second latchmagnet 2158 is mounted to the second end 2153. The first and secondlatch magnets 2156 and 2158 are each attracted to the magnetic outerhousing 2179 (see FIGS. 34A and 34B). Referring to FIG. 34A, attractionbetween the first latch magnet 2156 (see FIG. 36 ) and the outer housing2179 maintains the shaft 2116 in the first position after the shaft 2116has been moved to the first position (by powering the coil 2177).Similarly, referring to FIG. 34B, attraction between the second latchmagnet 2158 (see FIG. 36 ) and the outer housing 2179 maintains theshaft 2116 in the second position after the shaft 2116 has been moved tothe second position (by powering the coil 2177). Thus, the shaft 2116may remain in a desired position after the coil 2177 is powered down.

The control signal 1180 (see FIG. 5E) selectively powers the coil 2177to move the movable magnet subassembly 2176 toward either the first endcap assembly 2032 or the second end cap assembly 2034. When the movablemagnet subassembly 2176 moves toward the first end cap assembly 2032,the shaft 2116 moves therewith toward the first position. Referring toFIG. 34A, after the shaft 2116 has moved to the first position, the coil2177 is powered down and attraction between the first latch magnet 2156(see FIG. 36 ) and the outer housing 2179 maintains the shaft 2116 inthe first position. On the other hand, when the movable magnetsubassembly 2176 moves toward the second end cap assembly 2034, theshaft 2116 moves therewith toward the second position. Referring to FIG.34B, after the shaft 2116 has moved to the second position, the coil2177 is powered down and attraction between the second latch magnet 2158(see FIG. 36 ) and the outer housing 2179 maintains the shaft 2116 inthe second position. Thus, additional power is not needed to maintainthe shaft 2116 in either the first position or the second position,which helps extend battery life in embodiments powered by one or morebatteries.

Referring to FIG. 37 , the actuator mounting portion 2190 is spacedinwardly from the first open end 2022 and optionally includes one ormore through-holes configured to receive the fastener(s) 2178 (see FIGS.34A and 34B). Referring to FIGS. 34A and 34B, the outer housing 2179 iscoupled to an inwardly facing side of the actuator mounting portion 2190by the fastener(s) 2178, which anchor the stationary coil subassembly2174 to the housing 2020. Referring to FIGS. 34A and 34B, the actuatormounting portion 2190 has a through-hole 2186 (see FIG. 37 ) configuredto allow the shaft 2116 to pass fully therethrough to position the firstpoppet valve assembly 2112 between the first and second seats “S1′” and“S2′.”

Referring to FIG. 38 , the housing 2020 (see FIGS. 34A and 34B) includesan internal support 2194 spaced inwardly from the second open end 2024.In the embodiment illustrated, the internal support 2194 extendsradially inward from the inner wall 2100. The internal support 2194 hasa through-hole 2196 formed therein. Referring to FIGS. 34A and 34B, thethrough-hole 2196 (see FIG. 38 ) is configured to allow the shaft 2116to pass therethrough to position the second poppet valve assembly 2114between the third and fourth seats “S3′” and “S4′.” Referring to FIGS.34A and 34B, the internal support 2194 abuts and helps position theouter housing 2179 of the actuator 2170. In the embodiment illustrated,the actuator mounting portion 2190 is coupled to an end of the outerhousing 2179 near the second seat “S2′” and the internal support 2194abuts an opposite end of the outer housing 2179 near the third seat“S3′.”

Referring to FIGS. 34A and 34B, the housing 2020 includes an intake bodyportion 2198 (also illustrated in FIG. 37 ) coupled to an exhaust bodyportion 2199 (also illustrated in FIG. 38 ). The valve-to-blower outlet2002, the air intake 2006, the aperture 2010, the first open end 2022,and the actuator mounting portion 2190 are formed in the intake bodyportion 2198. The blower-to-valve inlet 2004, the exhaust outlet 2008,the second open end 2024, and the internal support 2194 are formed inthe exhaust body portion 2199.

Referring to FIG. 34A, in the first configuration, the first poppetvalve assembly 2112 is pressed against the second seat “S2′,” and thesecond poppet valve assembly 2114 is pressed against the fourth seat“S4′.” Referring to FIGS. 5A and 34A, in the first configuration, thefirst poppet valve assembly 2112 permits the flow of gas 252 from theaccumulator 202 to flow through the air intake 2006, out thevalve-to-blower outlet 2002, and into the blower 222. Further, the firstpoppet valve assembly 2112 blocks the gas 252 from directly entering theaperture 2010, thus sealing the aperture 2010 from both the air intake2006 and the valve-to-blower outlet 2002. At the same time, the secondpoppet valve assembly 2114, which is pressed against the fourth seat“S4′,” closes the exhaust outlet 2008 and permits the flow of the gas252 to the main ventilator connection 104. In this configuration, thegas 252 from the accumulator 202 entering the air intake 2006 isdirected to the blower 222 through the valve-to-blower outlet 2002. Thegas 252 is then blown by the blower 222 into the blower-to-valve inlet2004 and out through the aperture 2010 to the main ventilator connection104.

Referring to FIG. 34B, in the second configuration, the first poppetvalve assembly 2112 is pressed against the first seat “S1′,” and thesecond poppet valve assembly 2114 is pressed against the third seat“S3′.” Referring to FIGS. 5B and 34B, in the second configuration, thefirst poppet valve assembly 2112 permits the flow of exsufflation gases253 from the main ventilator connection 104 to flow through the aperture2010, out the valve-to-blower outlet 2002, and into the blower 222.Further the first poppet valve assembly 2112 blocks the flow ofexsufflation gases to the air intake 2006, thus preventing gas 252 fromthe accumulator 202 from reaching the valve-to-blower outlet 2002. Atthe same time, the second poppet valve assembly 2114, which is pressedagainst the third seat “S3′,” opens the exhaust outlet 2008 and blocksthe flow of the exsufflation gases 253 to the aperture 2010. In thisconfiguration, the exsufflation gases 253 from the main ventilatorconnection 104 entering the aperture 2010 are directed to the blower 222through the valve-to-blower outlet 2002. The exsufflation gases 253 arethen blown by the blower 222 into the blower-to-valve inlet 2004 and outthrough the exhaust outlet 2008.

In the embodiment illustrated, the cough assist valve 2000 (see FIGS.34A and 34B) includes the ports 275A, 275B and 275C (described below andillustrated in FIGS. 5A and 5B) formed in the housing 2020 (see FIGS.34A and 34B). Referring to FIG. 38 , the ports 275A and 275B may beformed in the exhaust body portion 2199. Referring to FIGS. 34A and 34B,the port 275C may be formed in the intake body portion 2198. However,this is not a requirement. Optionally, referring to FIG. 37 , the coughassist valve 2000 includes the port 275D configured to be connected to aredundant airway pressure transducer (not shown).

The cough assist valve, whether it be the cough assist valve 204 or thecough assist valve 2000, is designed so that the pressures workingagainst the first and second poppet valve assemblies 1112 and 1114 ofcough assist valve 204 or the first and second poppet valve assemblies2112 and 2114 of cough assist valve 2000, are balanced. This results inthe actuator 1170 of cough assist valve 204 and the actuator 2170 ofcough assist valve 2000 never having to work against the patientpressure. Since all of the seat areas of seats S1-S4 of cough assistvalve 204 are the same, as are all of the seat areas of seats S1′-S4′ ofcough assist valve 2000, the patient pressure inside the cough assistvalve coming through port 1010 (e.g., see FIGS. 5C and 5D) workingagainst the poppet valve assemblies of the cough assist valve, createsforces that are equal and opposite. Thus, the force on the first andsecond poppet valve assemblies 1112 and 1114 of cough assist valve 204,when seated against the first and third seats S1 and S3, respectively,and when seated against the second and fourth seats S2 and S4,respectively, are substantially equal and in opposite directions.Similarly, the force on the first and second poppet valve assemblies2112 and 2114 of cough assist valve 2000, when seated against the firstand third seats S1′ and S3′, respectively, and when seated against thesecond and fourth seats S2′ and S4′, respectively, are substantiallyequal and in opposite directions. If the forces on the first and secondpoppet valve assemblies of the cough assist valve were not balanced, theactuator 1170/2170 of the cough assist valve would need to be muchlarger, and the power required to actuate the actuator would be greater.

As mentioned above, the ventilation assembly 190 may include either thecough assist valve 204 or the cough assist valve 2000. If theventilation assembly 190 includes the cough assist valve 204, duringnormal ventilation, the cough assist valve 204 is in the firstconfiguration shown in FIGS. 5A and 18A. On the other hand, if theventilation assembly 190 includes the cough assist valve 2000 (see FIGS.34A and 34B), during normal ventilation, the cough assist valve 2000 isin the first configuration shown in FIG. 34A.

Referring to FIG. 5A, at the beginning of the inspiratory phase of abreath (and the beginning of the insufflation phase of a cough), the air114 may be drawn into the ventilator 100 (see FIGS. 1 and 4 ) throughthe patient air intake 116, which may be configured to filter dustand/or other types of particles from the air. At least a portion of theair 114 flows into the accumulator 202 where the air 114 may optionallybe mixed with oxygen 250 received from the oxygen assembly 210, the lowpressure oxygen 128 (received from the external low-pressure oxygensource 118 depicted in FIG. 1 ), combinations and/or sub-combinationsthereof, and the like. As illustrated in FIG. 4 , the high pressureoxygen 132 (received from the high-pressure external oxygen source 120depicted in FIG. 1 ) flows into the oxygen assembly 210 and may bedelivered to the accumulator 202 (see FIG. 5A) as the oxygen 250.

Referring to FIG. 5A, the accumulator 202 may also serve as a mufflerfor the patient air intake 116.

The inlet silencer 229 helps muffle sounds created by the oxygenassembly 210 (e.g., by a compressor 302 illustrated in FIG. 7A).

The oxygen sensor 227 is connected to the accumulator 202 and measuresan oxygen concentration value of the gas(es) inside the accumulator 202.This value approximates the oxygen concentration value of the gas 252that exits the accumulator 202. Referring to FIG. 5E, the oxygen sensor227 provides an oxygen concentration signal 276 encoding the oxygenconcentration value to the control system 220. The control system 220processes the oxygen concentration signal 276 to obtain a measure of howmuch oxygen is in the gas 252 (e.g., expressed as a percentage).Referring to FIG. 4 , the output information 198 sent by the controlsystem 220 to the user interface 200 may include the measure of how muchoxygen is in the gas 252. The user interface 200 may display thismeasure to the user (e.g., the patient 102 depicted in FIG. 1 ).

Referring to FIG. 5A, optionally, the accumulator 202 includes or isconnected to the low-pressure oxygen inlet 126. When the low-pressureoxygen 128 is supplied by the external low-pressure oxygen source 118(see FIG. 1 ), the control system 220 may not control the resultingoxygen concentration flowing to the patient 102. In other words, thelow-pressure oxygen 128 may simply flow into the accumulator 202, bemixed with the air 114, and pushed into the patient circuit 110 (seeFIG. 1 ) by the blower 222. When this occurs, the ventilator 100 doesnot control the oxygen concentration delivered to the patient 102 in theinspiratory gases 108 (see FIG. 1 ), but does control the delivery ofthe inspiratory gases 108 during the inspiratory phase of each breath.

The gas 252 exiting the accumulator 202 includes the air 114 andoptionally one or more of the oxygen 250 and the oxygen 128. The gas 252may be conducted via the flow line 214 to the internal flow transducer212. The gas 252 flows through the internal flow transducer 212, whichmeasures a flow rate of the gas 252 and provides a flow signal 270 (seeFIG. 5E) encoding the flow rate to the control system 220 (see FIG. 5E).The flow signal 270 may be implemented as an analog electric signal.Referring to FIG. 5E, the control system 220 uses the flow signal 270 tocontrol the blower 222. By way of a non-limiting example and as shown inFIG. 5A, the internal flow transducer 212 may be implemented using aflow transducer having a fixed orifice differential pressureconfiguration.

The internal flow transducer 212 may be used to detect when the patient102 (see FIG. 1 ) has initiated a breath. In particular, the internalflow transducer 212 may be used in this manner when the patient circuit110 (see FIG. 1 ) is implemented as a passive patient circuit (e.g., thepassive patient circuit 170, the passive patient circuit 440, and thelike). The flow of gases through the flow line 214 is not determinedentirely by the blower 222. Instead, the patient's breathing efforts maycause a change in the flow rate through the flow line 214. Thus, thecontrol system 220 may identify that the patient 102 has initiated abreath by identifying a change in the flow rate (encoded in the flowsignal 270) through the flow line 214.

The internal flow transducer 212 may include or be connected to an autozero solenoid valve SV5 configured to be selectively activated anddeactivated by a control signal 285 (see FIG. 5E) sent by the controlsystem 220. The internal flow transducer 212 may drift over time,causing flow rate measuring errors. To compensate for this error,occasionally (e.g., periodically) the control system 220 energizes (oractivates) the auto zero solenoid valve SV5 (using the control signal285) and determines an offset value for the internal flow transducer212. After determining the offset value, the control system 220 uses theoffset value to compensate future readings (based on the flow signal270) accordingly.

Referring to FIG. 5A, after the internal flow transducer 212, the gas252 is conducted into the blower 222 via the flow line 214 and the coughassist valve 204 (or the cough assist valve 2000). Referring to FIG. 5E,the blower 222 may be implemented as a radial blower driven by a motor272. By way of a non-limiting example, the motor 272 may be implementedas a brushless direct current motor. By way of additional non-limitingexamples, the blower 222 may be implemented as a compressor, a pump, andthe like. The motor 272 has an operating speed that is controlled by thecontrol system 220. By way of a non-limiting example, the control system220 may continuously control the operating speed of the motor 272.

Referring to FIG. 5A, the gas 252 flows out of the blower 222 and intothe cough assist valve 204 (or the cough assist valve 2000). The ports275A-275C are each configured to provide access to the flow of the gas252 in the cough assist valve 204 (or the cough assist valve 2000). Theflow line 273 conducts the flow of the gas 252 from the cough assistvalve 204 (or the cough assist valve 2000) to the internal bacteriafilter 230.

Referring to FIG. 5A, the airway pressure transducer 224 measures airwaypressure of the gas 252 flowing out of the blower 222 and toward themain ventilator connection 104. In the embodiment illustrated, theairway pressure transducer 224 is connected to the port 275C. Referringto FIG. 5E, the airway pressure transducer 224 provides an electricalpressure signal 274 encoding these pressure values to the control system220. The electrical pressure signal 274 is used to control patientpressure during the inspiratory and exhalation phases. The electricalpressure signal 274 is also used by the monitoring and alarm systems 221(see FIG. 4 ). Optionally, the ventilator 100 (see FIGS. 1 and 4 ) mayinclude one or more redundant airway pressure transducers (not shown)like the airway pressure transducer 224 to provide a failsafe backup forthe airway pressure transducer 224. In embodiments including a redundantairway pressure transducer (not shown), the redundant airway pressuretransducer may be connected to the port 275D (see FIG. 17B).

The airway pressure transducer 224 may be used by the control system 220to detect a pressure change and in response to detecting a pressurechange, instruct the blower 222 to increase or decrease its speed toadjust the pressure inside the flow line 273. Thus, the control system220 may use the electrical pressure signal 274 to deliver pressureventilation and/or help ensure the pressure inside the flow line 273does not exceed an user supplied peak inspiratory pressure value (e.g.,entered via the pressure control input 237 depicted in FIG. 6 ).

Referring to FIG. 5A, the airway flow transducer module 225 includes adifferential pressure transducer PT4, auto zero solenoid valves SV1 andSV2, and purge solenoid valves SV3 and SV4. Referring to FIG. 5E, thecontrol system 220 may selectively activate or deactivate the solenoidvalves SV1-SV4 using control signals 281-284, respectively.

Referring to FIG. 1 , as mentioned above, the patient circuit 110 mayinclude the one or more optional ports 111. FIG. 5A illustrates animplementation of the ventilation assembly 190 configured for use withthe patient circuit 110 implemented as an active patient circuit (e.g.,the active patient circuit 600 depicted in FIG. 3A, and the like). Inalternate embodiments configured for use with the patient circuit 110implemented as a passive patient circuit (e.g., the passive patientcircuit 170 depicted in FIG. 2A, the passive patient circuit 440depicted in FIG. 2B, and the like), the ports 275A and 275B, the airwayflow transducer module 225, and the exhalation control assembly 226 maybe omitted from the ventilation assembly 190.

The airway flow transducer module 225, and the exhalation controlassembly 226 illustrated in FIG. 5A are configured for use with anactive patient circuit (e.g., the active patient circuit 600 depicted inFIG. 3A) that includes the airway flow transducer 648 (see FIG. 3G).Referring to FIG. 5A, the first and second ports 111A and 111B (see FIG.3C) send first and second pressure signals 109A and 109B, respectively,(e.g., via separate lines or channels) to the differential pressuretransducer PT4. The differential pressure transducer PT4 has input portsPA and PB configured to receive the first and second pressure signals109A and 109B, respectively. The differential pressure transducer PT4determines a differential pressure based on the first and secondpressure signals 109A and 109B, converts the differential pressure to asignal 277 (see FIG. 5E), and (as illustrated in FIG. 5E) transmits thesignal 277 to the control system 220 for further processing thereby. Byway of a non-limiting example, the signal 277 may be an analog signal.

The signal 277 may be used to detect when the patient 102 (see FIG. 1 )has initiated a breath. The flow of gases through the active patientcircuit 600 (see FIG. 3A) is not determined entirely by the blower 222.Instead, the patient's breathing efforts may cause a change in the flowrate through the active patient circuit 600. Thus, the control system220 may identify that the patient 102 has initiated a breath byidentifying a change in the flow rate (encoded in the signal 277)through the active patient circuit 600.

The auto zero solenoid valves SV1 and SV2 are connected to the inputports PA and PB, respectively, of the differential pressure transducerPT4. Further, each of the auto zero solenoid valves SV1 and SV2 isconnected to ambient pressure. The differential pressure transducer PT4can drift over time causing flow measuring errors. To compensate forthis error, occasionally (e.g., periodically) the control system 220energizes (or activates) the auto zero solenoid valves SV1 and SV2(using the control signals 281 and 282, respectively) and determines anoffset value for the differential pressure transducer PT4. Then, thecontrol system 220 deactivates the auto zero solenoid valves SV1 and SV2(using the control signals 281 and 282, respectively). After determiningthe offset value, the control system 220 uses the offset value tocompensate future readings (based on the signal 277) accordingly.

The purge solenoid valves SV3 and SV4 are connected to the port 275A.Referring to FIG. 5E, the control system 220 occasionally (e.g.,periodically) energizes (or activates) the purge solenoid valves SV3 andSV4 (using the control signals 283 and 284, respectively), which allowsdry gas from the cough assist valve 204 illustrated in FIG. 5A (or thecough assist valve 2000 illustrated in FIG. 34A) to flow through thelines, ports, and/or channels (e.g., the optional multi-lumen tubeconnection 103, the channels 626A and 626B, the channels 632A and 632B,the ports 111A and 111B, and the like) conducting the pressure signals109A and 109B to purge those structures of any moisture that may havecondensed from the humid patient breathing gas.

Referring to FIG. 5E, the exhalation control assembly 226 includes anaccumulator A2, a pressure transducer PT8, and solenoid valves SV6-SV8.The accumulator A2 has three ports 267-269 and an internal pressure(referred as the “pilot pressure”). The pressure transducer PT8 isconnected to the accumulator A2, measures the internal pressure insidethe accumulator A2, and transmits this value to the control system 220in an electrical pressure signal 271 (see FIG. 5E).

Referring to FIG. 5E, the solenoid valves SV6-SV8 are configured to beselectively activated and deactivated by control signals 286-288,respectively, sent by the control system 220 to the solenoid valvesSV6-SV8, respectively. Turning to FIG. 5A, the solenoid valve SV6 isconnected to the first port 267 of the accumulator A2, the port 275B,and the pilot port 111C (see FIG. 3C) of the active patient circuit 600(see FIG. 3A). The solenoid valve SV7 is connected to the second port268 of the accumulator A2 and the port 275B. The solenoid valve SV8 isconnected between the third port 269 of the accumulator A2 and theoutlet port 166.

The exhalation control assembly 226 provides the pilot pressure (fromthe accumulator A2) to the pilot port 111C (see FIG. 3C) of the activepatient circuit 600 (see FIG. 3A), which as described above, controlsthe active exhalation valve assembly 604. At the start of theinspiratory phase of a breath, the control system 220 activates thesolenoid valve SV6 (using the control signal 286), which connects thepressure of the gases 252 (via the port 275B) to the pilot port 111C.This closes the active exhalation valve assembly 604. At the end of theinspiratory phase of a breath, the control system 220 deactivates thesolenoid valve SV6 (using the control signal 286), which connects theinternal pressure of the accumulator A2 (or the pilot pressure) to theactive exhalation valve assembly 604, which opens the active exhalationvalve assembly 604.

Similarly, at the start of the insufflation phase of a cough, thecontrol system 220 activates the solenoid valve SV6 (using the controlsignal 286), which connects the pressure of the gases 252 (via the port275B) to the pilot port 111C. This closes the active exhalation valveassembly 604. At the end of the insufflation phase, the control system220 deactivates the solenoid valve SV6 (using the control signal 286),which connects the internal pressure of the accumulator A2 (or the pilotpressure) to the active exhalation valve assembly 604. As discussedbelow, instead of opening the active exhalation valve assembly 604, thismaintains the active exhalation valve assembly 604 in the closedconfiguration. It is noted that during the beginning of the exsufflationphase, the double bellows member 644 may move into the open position asa result of the patient pressure applied to the double bellows memberbeing higher than ambient, but will automatically close when thepressure provided by the patient 102 drops below ambient.

The control system 220 uses the solenoid valves SV7 and SV8 to controlthe pilot pressure inside the accumulator A2 using feedback provided bythe pressure transducer PT8 (via the electrical pressure signal 271depicted in FIG. 5E) to set a pilot pressure for the exhalation phase ofa breath that will achieve the desired PEEP. For example, the controlsystem 220 may lower the pilot pressure inside the accumulator A2 byactivating the solenoid valve SV8 (using the control signal 288) to ventsome of the gases inside the accumulator A2 via the outlet port 166 asthe exhaust 167. Conversely, the control system 220 may increase thepilot pressure by activating the solenoid valve SV7 (using the controlsignal 287) to add some of the gases 252 (obtained via the port 275B) tothe inside of the accumulator A2.

Referring to FIG. 5E, the control system 220 uses the electricalpressure signal 274 (received from the airway pressure transducer 224)to help control the blower 222. The control system 220 sends a controlsignal 278 to the motor 272, which directs the blower 222 to provide adesired flow rate and/or a desired amount of pressure to the patient102. As mentioned above, the flow signal 270 is used to help control theflow rate of the gas 252 during the inspiratory and exhalation phases ofa breath. Similarly, the electrical pressure signal 274 is used tocontrol the patient pressure during the inspiratory and exhalationphases of a breath. The flow signal 270 may be used to help control theflow rate of the gas 252 during the insufflation phase and/or the flowrate of the exsufflation gases 253 during the exsufflation phase of acough. Similarly, the electrical pressure signal 274 is used to controlthe patient pressure during the insufflation phase and/or theexsufflation phase of a cough.

As explained above, the ventilator 100 adjusts the pressure inside thepatient circuit 110 (e.g., the passive patient circuit 440 illustratedin FIG. 2B) to achieve the preset inspiratory pressure during theinspiratory phase, the baseline pressure or PEEP during the exhalationphase, and PEEP during the pause between the inspiratory and exhalationphases. These adjustments (and adjustments performed during a coughassist maneuver) are made by the control system 220, which monitors theelectrical pressure signal 274, and uses the control signal 278 toincrease or decrease the speed of the motor 272 to achieve the desiredpressure inside the patient circuit 110.

The ambient pressure transducer 228 measures an atmospheric pressurevalue. The ambient pressure transducer 228 provides an ambientelectrical pressure signal 280 encoding the atmospheric pressure valueto the control system 220. The control system 220 uses the ambientelectrical pressure signal 280 to correct the flow rate values (receivedvia the flow signal 270), and/or the exhaled tidal volume value(calculated by the control system 220) to desired standard conditions.

Referring to FIG. 5A, as mentioned above, the flow line 273 conducts theflow of the gas 252 from the cough assist valve 204 (or the cough assistvalve 2000) to the internal bacteria filter 230. After the gas 252passes through the internal bacteria filter 230, they exit the internalbacteria filter 230 as the gases 112 and enter the patient circuit 110(see FIG. 1 ) via the main ventilator connection 104. The internalbacteria filter 230 helps prevent bacteria in the patient circuit 110from contaminating the ventilator 100.

User Interface

FIG. 6 is a block diagram illustrating some exemplary components of theuser interface 200. As mentioned above, FIG. 4 illustrates the outputinformation 198 sent by the control system 220 to exemplary componentsof the user interface 200, and the input information 196 received by thecontrol system 220 from exemplary components of the user interface 200.

Referring to FIG. 6 , the user interface 200 is configured to receiveoperating parameter values from a user (e.g., a clinician) and todisplay information to the user. For example, the user interface 200 mayinclude a display device 240 (e.g., a liquid crystal display), a modeinput 235, an inspiratory time input 236, a pressure control input 237,a pressure support input 238, an activate oxygen generator input 239 foractivating oxygen generation (described below), a tidal volume input242, an oxygen flow equivalent 244, a fraction of inspired oxygen(“FI02”) input 246, a breath rate input 247, an oxygen pulse volumeinput 251, an activate cough assist input 241, an activate suction input248 for activating the suction assembly 152 (see FIG. 1 ), and anactivate nebulizer input 249 for activating the nebulizer assembly 162(see FIG. 1 ).

The beginning of the inspiratory phase is referred to as “initiation.”The mode input 235 is configured to receive an indication as to whetherthe ventilator 100 determines when each breath is initiated or thepatient 102 determines when each breath is initiated. The breath rateinput 247 is configured to receive a rate (e.g., breaths per minute) atwhich breaths are to be delivered. If the user has indicated (using themode input 235) that the ventilator 100 determines when each breath isinitiated, the ventilator 100 will deliver breaths in accordance withthe rate received by the breath rate input 247 (e.g., at regularly timedintervals). On the other hand, if the user has indicated (using the modeinput 235) that the patient 102 initiates each breath, the ventilator100 will automatically deliver breaths as needed to ensure the patient102 receives breaths at least as frequently as indicated by the ratereceived by the breath rate input 247.

The ventilator 100 may identify the end of the inspiratory phase usingtime or a rate of flow of the gases 112 to the patient 102. In thelatter case, the patient 102 determines when the inspiratory phase ends.The inspiratory time input 236 is configured to receive a valueindicating a duration T_(i) from the initiation of each breath to theend of the inspiratory phase. The ventilator 100 may use the value(indicating the duration T_(i)) to identify the end of the inspiratoryphase. The pressure support input 238 receives an indication that theuser would like to use the rate of flow of the gases 112 to the patient102 (instead of the value indicating the duration T_(i)) to end theinspiratory phase. For example, the ventilator 100 may end theinspiratory phase of a breath when the flow rate of the gases 112 isonly about 25% of a peak flow rate that occurred during the breath.

The ventilator 100 is configured to deliver the gases 112 alone, or acombination of the gases 112 and the pulses of oxygen 140. As mentionedabove, the ventilator 100 may be configured to provide both traditionalvolume controlled ventilation and pressure controlled ventilation. Touse pressure control, the user may use the pressure control input 237 toenter a peak inspiratory pressure value. The ventilator 100 uses thepeak inspiratory pressure value to configure the gases 112 alone, or thecombination of the gases 112 and the pulses of oxygen 140 such that thepressure during the inspiratory phases is at most the peak inspiratorypressure value.

The FI02 input 246 is configured to receive an oxygen concentrationvalue. The ventilator 100 uses the oxygen concentration value toconfigure the gases 112 to have an oxygen concentration equal to orapproximating the oxygen concentration value.

The oxygen pulse volume input 251 is configured to receive an oxygenpulse volume value (e.g., expressed in milliliters, or a value within apredefined range, such as from 1 to 10, and the like). The ventilator100 uses the oxygen pulse volume value to configure each of the pulsesof oxygen 140 to have a volume equal to or approximating the oxygenpulse volume value.

The tidal volume input 242 is configured to receive a desired totaltidal volume value. Referring to FIG. 15A, the ventilator 100 uses thedesired total tidal volume value to output a volume of the gases 112(illustrated by area 586 and described below) and one of the pulses ofoxygen 140 (illustrated by area 584 and described below) during eachbreath. For each breath delivered, the total tidal volume delivered isthe combined volumes of gases 112 and the pulse of oxygen 140 deliveredduring the breath.

The oxygen flow equivalent 244 is configured to receive a desired oxygendelivery rate (expressed in liters per minute) that identifies a rate atwhich a hypothetical continuous oxygen flow may be bled into aconventional ventilator or the patient circuit 110 (see FIG. 1 ) from anexternal source (e.g., a stand-alone oxygen concentrator). Theventilator 100 uses this value to configure each of the pulses of oxygen140 (see FIG. 1 ) to deliver an amount of oxygen that would provideequivalent oxygenation to the patient 102 (see FIG. 1 ) as thehypothetical continuous oxygen flow.

The activate cough assist input 241 indicates that the user would liketo perform a cough assist maneuver (discussed below).

Oxygen Assembly

FIG. 7A is a schematic diagram illustrating some exemplary components ofthe oxygen assembly 210. FIG. 7B illustrates the control signals 260sent by the control system 220 to exemplary components of the oxygenassembly 210, and the data signals 262 received by the control system220 from exemplary components of the oxygen assembly 210.

Referring to FIG. 7A, the oxygen assembly 210 is configured to receivethe high-pressure oxygen 132 and/or generate oxygen 346 (see FIG. 8B)and provide the oxygen 250 to the accumulator 202 (see FIG. 5A) of theventilation assembly 190 and/or provide the pulses of oxygen 140 to thepatient oxygen outlet 105. The oxygen assembly 210 may be configured toprovide up to about two liters per minute (“LPM”) of approximately 90%pure oxygen. In the embodiment illustrated, the oxygen assembly 210includes an adsorption bed 300, the compressor 302, a first rotary valveassembly 306, two pressure transducers PT2 and PT3, two pressureregulators R1 and R2, an outlet silencer 311, optional solenoid valvesSV9 and SV10, an oxygen tank 312, an oxygen sensor 314, a metering valve320, and an optional second rotary valve assembly 330. Together thecompressor 302, the first rotary valve assembly 306, the adsorption bed300, and the pressure regulators R1 and R2 may be characterized as beingan oxygen generator or oxygen concentrator. The oxygen generatorillustrated in the figures and described below implements a vacuumpressure swing adsorption (“VPSA”) process. In alternate embodiments,the ventilator 100 may include an oxygen generator that implements atleast one of a polymer membrane separation process, an ion transportseparation process, a cryogenic process, and the like. Further, the VPSAprocess described below is a subset of Pressure Swing Adsorption (PSA)and the oxygen generator may be configured to implement a PSA processother than the VPSA process described below.

The adsorption bed 300 is configured to harvest oxygen from the air 114received via the patient air intake 116. As will be explained below, theadsorption bed 300 may be configured to at least partially implement aVPSA process that includes a cycle with four phases (described below).The cycle alternately generates the oxygen 346 (see FIG. 8B) and thenitrogen-rich gas 122. As the ventilator 100 operates, the cycle isrepeated until enough oxygen has been generated to fill the oxygen tank312. When the oxygen tank 312 is full, the cycles are halted or sloweduntil a sufficient amount of the oxygen in the oxygen tank 312 has beenremoved. Then, the cycles are resumed again or sped up as appropriate.The nitrogen-rich gas 122 generated by each cycle is exhausted to theoutside environment via the outlet vent 124.

FIGS. 8A-8D are block diagrams illustrating some exemplary components ofthe adsorption bed 300. Referring to FIGS. 8A-8D, in the embodimentillustrated, the adsorption bed 300 includes at least one housing 340having a first end 341 opposite a second end 343. The housing 340contains a bed of nitrogen adsorbent material 344 (such as zeolite)between its first and second ends 341 and 343. The bed of nitrogenadsorbent material 344 preferentially absorbs nitrogen. For ease ofillustration, the adsorption bed 300 will be described as including asingle housing containing a single bed of nitrogen adsorbent material.In alternate embodiments, the adsorption bed 300 may include two or morebeds like the bed of nitrogen adsorbent material 344 that are eachhoused inside separate housings like the housing 340.

As mentioned above, the VPSA process includes a cycle with four phases.FIG. 8A illustrates the adsorption bed 300 during a first phase.Referring to FIG. 8A, during the first phase, the air 114 is pumped intothe housing 340 by the compressor 302 (see FIG. 7A). When the housing340 is pressurized with the air 114 (by the compressor 302), nitrogen inthe air is preferentially adsorbed by the bed of nitrogen adsorbentmaterial 344, which leaves behind unadsorbed oxygen. The bed of nitrogenadsorbent material 344 may include interstitial spaces in which theunadsorbed oxygen is held or trapped.

FIG. 8B illustrates the adsorption bed 300 during a second phase of acycle of the VPSA process. During the second phase, the oxygen 346 ispumped from the housing 340. The oxygen 346 flows from the interstitialspaces and into the oxygen tank 312 (see FIG. 7A).

FIG. 8C illustrates the adsorption bed 300 during a third phase of acycle of the VPSA process. During the third phase, the nitrogen-rich gas122 is pulled from the bed of nitrogen adsorbent material 344 in thehousing 340 (by the compressor 302 illustrated in FIG. 7A) and vented tothe outside environment via the outlet vent 124 (see FIG. 7A).

FIG. 8D illustrates the adsorption bed 300 during a fourth phase of acycle of the VPSA process. During the fourth phase, a flow of “purge”oxygen 348 (e.g., from the oxygen tank 312 illustrated in FIG. 7A) maybe used to help draw out the nitrogen-rich gas 122 and regenerate thebed of nitrogen adsorbent material 344.

Returning to FIG. 7A, the oxygen 346 (see FIG. 8B) removed from theadsorption bed 300 flows through the pressure regulator R2, and into theoxygen tank 312 where the oxygen 346 is stored. While this is occurring,the metering valve 320 may be closed, and the pressure regulator R1 maybe closed to prevent flow back into the adsorption bed 300.Alternatively, the metering valve 320 may be at least partially open toallow some of the oxygen 346 to flow to the optional second rotary valveassembly 330.

During each cycle, the compressor 302 is configured to alternately pushthe air 114 into the adsorption bed 300 (through the first rotary valveassembly 306) and pull the nitrogen-rich gas 122 out of the adsorptionbed 300 (through the first rotary valve assembly 306). The compressor302 may be driven by a motor 350 and may include a sensor 352 (e.g., anencoder) configured to provide a signal 354 encoding the direction andspeed of rotation of the motor 350 to the control system 220. Referringto FIG. 7B, the motor 350 is configured to receive instructions from thecontrol system 220 encoded in a control signal 356. The instructions inthe control signal 356 instruct the motor 350 to switch on or off and/orindicate in which direction the motor 350 is to rotate when switched on.Further, the control signal 356 may instruct the motor 350 at whichspeed to run. Referring to FIG. 7A, when the motor 350 runs in a firstdirection, the compressor 302 pushes air into the adsorption bed 300. Onthe other hand, when the motor 350 runs in a second direction, thecompressor 302 pulls the nitrogen-rich gas 122 (see FIGS. 8C and 8D)from the adsorption bed 300. By way of a non-limiting example, the motor350 may be implemented as a brushless direct current motor.

FIG. 9 is an illustration of the metering valve 320. Referring to FIG. 9, the pressure transducer PT3 is connected across the metering valve320. Thus, the pressure transducer PT3 may determine a pressuredifferential value across the metering valve 320. Referring to FIG. 7B,the pressure transducer PT3 provides a pressure differential signal 358encoding the pressure differential value to the control system 220.

Referring to FIGS. 7B and 9 , the metering valve 320 may be driven by astepper motor 322 configured to receive a control signal 360 from thecontrol system 220 encoding a stepper position value. The stepper motor322 is configured to move to the stepper position value encoded in thecontrol signal 360. In the embodiment illustrated, the metering valve320 is a stepper driven proportioning valve characterized by threevariables: (1) valve position, (2) differential pressure across thevalve (as measured by the pressure transducer PT3), and (3) flow rate.When a particular flow rate is desired (e.g., entered by the user viathe flow rate input 248 depicted in FIG. 6 ), the control system 220uses the pressure differential signal 358 (encoding the pressuredifferential value) and the particular flow rate to “look up” acorresponding stepper position value in a characterization table 362. Inother words, the characterization table 362 stores stepper positionvalues each associated with a flow rate value and a pressuredifferential value. Thus, a particular pressure differential value and aparticular flow rate value may be used by the control system 220 todetermine a stepper position value. Then, the control system 220 encodesthe stepper position value in the control signal 360 and sends it to thestepper motor 322. This process may be repeated occasionally (e.g.,every few milliseconds) to provide an instantaneously desired oxygenflow rate.

Referring to FIG. 9 , a position sensor 368 may be operatively coupledto the metering valve 320 and used to determine a home position. Theposition sensor 368 provides a position signal 370 to the control system220 that encodes whether the metering valve 320 is in the home position(e.g., true or “on”) or at a position other than the home position(e.g., false or “off”).

Referring to FIG. 7A, the pressure regulator R2 may be characterized asbeing a back pressure regulator. The pressure regulator R2 may beconfigured to prevent the pressure inside the adsorption bed 300 fromexceeding a first threshold pressure value (e.g., approximately 10pounds per square inch (“PSIG”)). For example, the pressure regulator R2may be configured to allow oxygen to flow automatically from theadsorption bed 300 when the pressure inside the adsorption bed 300reaches the first threshold value. The pressure regulator R2 may also beconfigured to prevent gases from flowing into the adsorption bed 300.This allows the pressure regulator R2 to control the pressure during thefirst phase (see FIG. 8A) and the second phase (see FIG. 8B).

The pressure regulator R1 may be characterized as being a vacuumregulator. The pressure regulator R1 may be configured to prevent thepressure inside the adsorption bed 300 from falling below a secondthreshold pressure value (e.g., approximately −7 PSIG). Thus, thepressure regulator R1 regulates the pressure in the adsorption bed 300to the second threshold pressure during the third phase (see FIG. 8C)and the fourth phase (see FIG. 8D). For example, the pressure regulatorR1 may be configured to allow oxygen to flow automatically into theadsorption bed 300 (e.g., from the oxygen tank 312) when the pressureinside the adsorption bed 300 falls below the second threshold value.The pressure regulator R1 may also be configured to prevent gases insidethe adsorption bed 300 from flowing out of the adsorption bed 300 towardthe metering valve 320 (see FIG. 1 ).

The optional solenoid valves SV9 and SV10 may be configured to maintainthe pressure inside the oxygen tank 312 between a minimum thresholdpressure value (e.g., approximately 4 PSIG) and a maximum thresholdpressure value (e.g., approximately 10 PSIG). The solenoid valves SV9and SV10 are connected in a parallel arrangement to a conduit or flowline (not shown) that conducts the high-pressure oxygen 132 (e.g., fromthe high-pressure oxygen source 120 illustrated in FIG. 1 ) to theoxygen tank 312. The control system 220 selectively activates anddeactivates the solenoid valves SV9 and SV10 using control signals 380and 382 (see FIG. 7B), respectively, to maintain the pressure in oxygentank 312 between the minimum and maximum threshold pressure values.Thus, together the control system 220 and the solenoid valves SV9 andSV10 perform the functions of a digital (on/off) regulator.

The control system 220 may automatically stop the oxygen assembly 210from performing the VPSA process when the high-pressure external oxygensource 120 is connected. For example, the control system 220 may slow orshut down the VPSA process when pressure in the oxygen tank 312 exceedsan upper threshold (e.g., 10 PSIG). In this manner, the control system220 may slow or shut down the VPSA process when the adsorption bed 300is operating or the high-pressure external oxygen source 120 isconnected. On the other hand, when the pressure inside the oxygen tank312 falls below a lower pressure threshold (e.g., 4 PSIG), the controlsystem 220 may restart or accelerate the VPSA process.

The oxygen tank 312 may be implemented as a rigid chamber configured tostore a predetermined amount of oxygen (e.g., about 56 cubic inches ofoxygen). The outlet silencer 311 helps muffle sounds created by thecompressor 302.

Referring to FIGS. 7A and 7B, the oxygen sensor 314 measures oxygenconcentration in the oxygen tank 312, and encodes an oxygenconcentration value in an oxygen concentration signal 378 provided tothe control system 220. The control system 220 may use the oxygenconcentration signal 378 to monitor the oxygen assembly 210 to ensure itis working properly. If the oxygen concentration signal 378 indicatesthe oxygen concentration is too low, the control system 220 may concludethat the oxygen assembly 210 is not functioning properly.

The pressure transducer PT2 monitors the pressure between the first andsecond rotary valve assemblies 306 and 330 (which may be characterizedas being a pump pressure supplied to the second rotary valve assembly330). Referring to FIG. 7B, the pressure transducer PT2 provides anelectrical pressure signal 374 encoding that pressure value to thecontrol system 220.

First Rotary Valve Assembly

FIG. 10A is a perspective view of a first side of an exemplaryembodiment of the first rotary valve assembly 306. FIG. 10B is aperspective view of a second side of the first rotary valve assembly 306opposite the first side. Referring to FIG. 10A, the first rotary valveassembly 306 includes a motor assembly 830 mounted to an outer housing832. The motor assembly 830 includes a stepper motor 833 (see FIG. 7B)and a shaft 836 (see FIGS. 10B and 10C). The stepper motor 833 isconfigured to rotate the shaft 836.

Referring to FIG. 10B, a position sensor 834 may be mounted on a printedcircuit board (“PCB”) 837 fastened to the outer housing 832 opposite themotor assembly 830. In such embodiments, the PCB 837 may include anopening through which an end of the shaft 836 opposite the motorassembly 830 may pass.

FIG. 10C depicts the first side of the first rotary valve assembly 306and the shaft 836 of the motor assembly 830. Other parts of the motorassembly 830 have been omitted in FIG. 10C. Referring to FIG. 10C, inthe embodiment illustrated, the outer housing 832 has an outer shapethat is generally cross or cruciform-shaped. Thus, the outer housing 832has four arms 841-844 that extend outwardly from a central region 845 ofthe outer housing 832. In the embodiment illustrated, the motor assembly830 (see FIG. 10A) is mounted to the central region 845.

FIG. 10D depicts the second side of the first rotary valve assembly 306with the outer housing 832 and the PCB 837 removed. As shown in FIG.10D, the arms 841-844 (see FIG. 10B) house poppet valves CV1-CV4,respectively. Inside the outer housing 832 (see FIG. 10B), the poppetvalves CV1 and CV3 are positioned opposite one another, and the poppetvalves CV2 and CV4 are positioned opposite one another. The first rotaryvalve assembly 306 includes a cam 850 mounted on the shaft 836 (seeFIGS. 10B and 10C) and configured to selectively actuate the poppetvalves CV1-CV4. The cam 850 rotates with the shaft 836 as the motorassembly 830 (see FIG. 10A) rotates the shaft 836. Referring to FIG. 7B,the position sensor 834 provides a position signal 835 to the controlsystem 220 that encodes whether the cam 850, the stepper motor 833 (seeFIGS. 10A and 10B), and/or the shaft 836 (see FIGS. 10B and 10C) is in ahome position (e.g., true or “on”) or at a position other than the homeposition (e.g., false or “off”).

Referring to FIG. 10C, each of the arms 841-844 is open at its distalend 846. The open distal ends 846 of the arms 841-844 are closed by endcaps 851-854, respectively. The end caps 851-854 may be fastened to theouter housing 832 by fasteners 855.

Referring to FIG. 10D, the arms 841-844 include inlet openings856A-856D, respectively, configured to receive a gas or mixture ofgases, and outlet openings 858A-858D, respectively, through which a gasor mixture of gases may exit.

Referring to FIG. 10D, each of the poppet valves CV1-CV4 includes anopen ended housing 860 with a lateral inlet 862 and a lateral outlet864. The lateral inlets 862 of the poppet valves CV1-CV4 are aligned andin fluid communication with the inlet openings 856A-856D, respectively,of the outer housing 832. Similarly, the lateral outlets 864 of thepoppet valves CV1-CV4 are aligned and in fluid communication with theoutlet openings 858A-858D, respectively, of the outer housing 832.

One or more seals 866 and 868 (e.g., O-ring type seals) may bepositioned between the outer housing 832 and the housing 860. Forexample, the seal 868 may be positioned between the lateral inlet 862and the lateral outlet 864. By way of another non-limiting example, oneof the seals 866 may be positioned between each of the open distal ends846 of the arms 841-844 and the end caps 851-854, respectively.

The poppet valves CV1-CV4 are substantially identical to one another.For the sake of brevity, only the poppet valve CV1 will be described indetail. FIG. 10E is an exploded perspective view of the poppet valveCV1, the end cap 851, and the fasteners 855. Referring to FIG. 10E, thehousing 860 has an open proximal end portion 870 opposite an open distalend portion 872. The open distal end portion 872 is closed by the endcap 851 when the end cap 851 is fastened to the outer housing 832.Similarly, the housings 860 of the poppet valves CV2-CV4 are closed attheir open distal end portions 872 by the end caps 852-853,respectively, when the end caps 852-854 are fastened to the outerhousing 832.

FIG. 10F is a cross sectional view of the first rotary valve assembly306 with the cam 850 positioned to open the poppet valves CV2 and CV4.FIG. 10G is a cross sectional view of the first rotary valve assembly306 with the cam 850 positioned to open the poppet valves CV1 and CV3.

Referring to FIG. 10F, a generally cylindrically shaped guide portion876 extends inwardly from the open proximal end portion 870 (see FIG.10E) of the housing 860. An open-ended channel 877 is formed in theguide portion 876. A shoulder 878 is formed on the inside the housing860 between the lateral inlet and outlet 862 and 864.

Turning to FIG. 10E, inside the housing 860, the poppet valve CV1 has apushrod 880 biased away from the end cap 851 by a biasing assembly 884.Referring to FIG. 10F, the pushrod 880 extends through the channel 877and exits the housing 860 through the open proximal end portion 870 (seeFIG. 10E). Turning to FIG. 10E, the pushrod 880 may have acircumferential recess 879 form near its proximal end portion 881.

A ring-shaped diaphragm 886 may extend around the pushrod 880 near theproximal end portion 881. In the embodiment illustrated, the diaphragm886 has a circular central portion P2 having a center aperture 887through which the pushrod 880 extends with the inner edge portion of thecentral portion P2 positioned within the recess 879, and thereby thecentral portion P2 firmly grips the pushrod 880. The diaphragm 886 mayclose and seal the open proximal end portion 870 of the housing 860.However, the diaphragm 886 may flex or stretch longitudinally to allowthe pushrod 880 to move longitudinally with respect to the housing 860.In the embodiment illustrated in FIG. 10F, the diaphragm 886 has acircular outer peripheral portion P1 positioned between the openproximal end portion 870 of the housing 860 and the outer housing 832,and thereby the outer peripheral portion P1 is firmly clamped in place.

Referring to FIG. 10E, the circular outer peripheral portion P1 of thediaphragm 886 is connected to the circular central portion P2 by acurved or contoured intermediate portion P3. The intermediate portion P3may be characterized as being a convolute. A circle positioned midwaybetween the outer peripheral portion P1 and the central portion P2 maybe characterized as being located at the center of the convolute. Thediaphragm 886 has an effective area which extends from the circle at thecenter of the convolute to the central portion P2.

Turning to FIG. 10E, the pushrod 880 has a distal end portion 882opposite the proximal end portion 881. The proximal end portion 881 hasa cam follower 883 (see FIGS. 10C and 10E) formed therein. In theembodiment illustrated, the proximal end portion 881 may taper outwardlyand be generally cone-shaped. The cam follower 883 (see FIG. 10C) may beimplemented as a planar or contoured lower surface of the proximal endportion 881.

A ring-shaped seat 896 is fixedly attached to the shoulder 878 formed onthe inside the housing 860. In the embodiment illustrated, the seat 896has a central through-hole 897 through which the pushrod 880 extendsunobstructed.

The distal end portion 882 of the pushrod 880 has a longitudinallyextending channel 885 formed therein. The channel 885 is open at thedistal end portion 882 of the pushrod 880. A disc-shaped poppet member892 is fastened to the distal end portion 882 of the pushrod 880 by afastener 894 (e.g., a bolt, screw, and the like) that extends into theopen end of the channel 885. Thus, the fastener 894 couples the poppetmember 892 to the distal end portion 882 of the pushrod 880, which movestherewith as a unit when the pushrod 880 moves inside the housing 860.

Referring to FIG. 10F, when the poppet member 892 is pressed against theseat 896, the poppet member 892 closes the central through-hole 897 anddivides the interior of the housing 860 into a proximal chamber 900 anda distal chamber 902. Thus, the poppet member 892 may seal the proximaland distal chambers 900 and 902 from one another. The lateral inlet 862is in communication with the proximal chamber 900, and the lateraloutlet 864 is in communication with the proximal chamber 900. On theother hand, referring to FIG. 10G, when the poppet member 892 is spacedapart distally from the seat 896, the central through-hole 897 isuncovered and the proximal and distal chambers 900 and 902 are incommunication with one another. Thus, in this configuration, a gas ormixture of gases may flow between the proximal and distal chambers 900and 902. In other words, a pathway is opened between the lateral inletand outlet 862 and 864.

The distal end portion 882 of the pushrod 880 is adjacent the biasingassembly 884. In the embodiment illustrated, the biasing assembly 884includes a biasing member 888 (e.g., a coil spring), and an end cap 890.The biasing member 888 applies an inwardly directed force on the pushrod880, which helps insure the pushrod 880 maintains contact with the cam850. The end cap 890 rests upon the fastener 894 and is positionedbetween the disc-shaped poppet member 892 and the end cap 851. Thebiasing member 888 extends between the end cap 890 and the end cap 851and applies the biasing force to the end cap 890, which translates thatforce to the fastener 894 and/or the poppet member 892. In turn, thefastener 894 and/or the poppet member 892 translates the biasing forceto the pushrod 880.

The cam 850 may be characterized as having two lobes or high points 910and 912 opposite one another. When one of the high points 910 and 912 isadjacent the cam follower 883 (see FIGS. 10C and 10E) of the pushrod 880of the poppet valve CV1, the high point 910 or 912 pushes the pushrod880 outwardly toward the end cap 851. This pushes the disc-shaped poppetmember 892 away from the seat 896 (as illustrated in FIG. 10G) and opensthe central through-hole 897. This opens the poppet valve CV1 and allowsa gas or mixture of gases to flow through the poppet valve CV1. On theother hand, as illustrated in FIG. 10G, when neither of the high points910 and 912 are adjacent the cam follower 883 (see FIGS. 10C and 10E) ofthe pushrod 880 of the poppet valve CV1, the pushrod 880 is biasedinwardly away from the end cap 851 by the biasing assembly 884. Thepushrod 880 thereby pulls the disc-shaped poppet member 892 toward theseat 896 causing the poppet member 892 to cover or close the centralthrough-hole 897. This closes the poppet valve CV1 and prevents a gas ormixture of gases from flowing through the poppet valve CV1.

Because the ventilator 100 may be required to function over a long lifespan (e.g., more than about 30,000 hours), the first rotary valveassembly 306 may experience about 15,000,000 VPSA cycles. To satisfythis requirement, each of the poppet valves CV1-CV4 may have a“balanced” valve configuration. Whenever one of the poppet valvesCV1-CV4 is closed, pressure inside the proximal chamber 900 acts uponboth the effective area of the diaphragm 886 and a portion of the poppetmember 892 covering (or closing) the central through-hole 897 of theseat 896. The area of the portion of the poppet member 892 covering (orclosing) the central through-hole 897 of the seat 896 is approximatelyequal to the effective area of the diaphragm 886. When the pressureinside the proximal chamber 900 is negative (or a vacuum), an inwardly(toward the proximal chamber 900) directed force acts upon the effectivearea of the diaphragm 886. At the same time, an inwardly (toward theproximal chamber 900) directed force acts on the portion of the poppetmember 892 covering the central through-hole 897 of the seat 896.Similarly, when the pressure inside the proximal chamber 900 ispositive, an outwardly (away from the proximal chamber 900) directedforce acts upon the effective area of the diaphragm 886 and an outwardly(or distally) directed force acts on the portion of the poppet member892 covering the central through-hole 897 of the seat 896. Thus, whenthe proximal chamber 900 is sealed by the poppet member 892, forcesdirected in opposite directions act upon the effective area of thediaphragm 886 and the area of the portion of the poppet member 892covering (or closing) the central through-hole 897 of the seat 896.Because (as mentioned above), the effective area of the diaphragm 886and the area of the portion of the poppet member 892 covering (orclosing) the central through-hole 897 of the seat 896 are approximatelyequal, net force on the pushrod 880 is zero. This balancing featurehelps reduce the force of the pushrod 880 on the cam follower 883 andthe cam 850, thereby reducing the wear and extending the life.

As explained above, each of the poppet valves CV1-CV4 is biased into aclosed position by its biasing assembly 884. Each of the poppet valvesCV1-CV4 includes the cam follower 883 (see FIGS. 10C and 10E) that abutsthe cam 850. As the cam 850 rotates, it pushes opposing ones of thepoppet valves CV1-CV4 outwardly opening them. If the poppet valves CV1and CV3 are in open positions, the poppet valves CV2 and CV4 are inclosed positions and vice versa. Referring to FIG. 7B, the first rotaryvalve assembly 306 (e.g., the stepper motor 833) is configured toreceive a control signal 376 from the control system 220 encoding a camposition. The first rotary valve assembly 306 (e.g., the stepper motor833) is also configured to rotate the cam 850 to the position encoded inthe control signal 376.

Referring to FIG. 7A, the poppet valve CV3 (see FIG. 10G) is connectedto the compressor 302 and the adsorption bed 300. The control system 220makes the pressure inside the distal chamber 902 of the poppet valve CV3less than the pressure inside the proximal chamber 900 of the poppetvalve CV3 by configuring the compressor 302 to provide suction to thedistal chamber 902.

The poppet valve CV1 (FIG. 10G) is connected to the compressor 302 andthe outlet vent 124. The control system 220 makes the pressure insidethe distal chamber 902 of the poppet valve CV1 less than the pressureinside the proximal chamber 900 of the poppet valve CV1 by configuringthe compressor 302 to push the nitrogen-rich gas 122 (see FIGS. 8C and8D) into the proximal chamber 900.

When the poppet valves CV1 and CV3 are open as illustrated in FIG. 10G,the poppet valve CV3 receives the nitrogen-rich gas 122 (see FIGS. 8Cand 8D) from the adsorption bed 300 and provides it to the compressor302. At the same time, the poppet valve CV1 allows the nitrogen-rich gas122 pumped from the adsorption bed 300 (via the poppet valve CV3) by thecompressor 302 to flow out of the compressor 302 and exit the ventilator100 via the outlet vent 124. Optionally, the poppet valve CV3 may beconnected to the second rotary valve assembly 330. As will be explainedbelow, the compressor 302 may provide the suction 154 to the suctionassembly 152 via the second rotary valve assembly 330.

Referring to FIG. 7A, the poppet valve CV4 (see FIG. 10F) is connectedto the compressor 302 and the patient air intake 116. The control system220 makes the pressure inside the proximal chamber 900 of the poppetvalve CV4 less than the pressure inside the distal chamber 902 of thepoppet valve CV4 by configuring the compressor 302 to provide suction tothe proximal chamber 900.

The poppet valve CV2 (see FIG. 10F) is connected to the compressor 302and the adsorption bed 300. The control system 220 makes the pressureinside the distal chamber 902 of the poppet valve CV2 greater than thepressure inside the proximal chamber 900 of the poppet valve CV2 byconfiguring the compressor 302 to provide the pressurized air 114 pumpedby the compressor 302 to the distal chamber 902.

When the poppet valves CV2 and CV4 are open as illustrated in FIG. 10F,the poppet valve CV4 allows the air 114 to be pumped via the patient airintake 116 into the compressor 302. At the same time, the poppet valveCV2 provides the pressurized air 114 from the compressor 302 to theadsorption bed 300. Optionally, the poppet valve CV2 may be connected tothe second rotary valve assembly 330. As will be explained below, thegases 164 provided to the second rotary valve assembly 330 may be usedto implement the nebulizer assembly 162.

As mentioned above, in the embodiment illustrated, the oxygen assembly210 generates the oxygen 364 (see FIG. 8B) using the VPSA process, whichmay have four phases that are labeled “PHASE 1,” “PHASE 2,” “PHASE 3,”and “PHASE 4” across the top of FIG. 11 .

In FIG. 11 , an upper line 400 depicts pressure experienced by the bedof nitrogen adsorbent material 344 (see FIGS. 8A-8D) during the fourphases of the VPSA process. Referring to FIG. 11 , the line 400 may bedetermined by the control system 220 based on the electrical pressuresignal 374 (see FIG. 7B) provided by the pressure transducer PT2. Alower line 410 depicts feed flow rate through the bed of nitrogenadsorbent material 344 (see FIGS. 8A-8D) during the four-phases of theVPSA process.

Lines 421 and 423 show that the poppet valves CV1 and CV3, respectively,are transitioned from open (“passing”) to closed (“not passing”) at thebeginning of the first phase and then the poppet valves CV1 and CV3 aretransitioned from closed (“not passing”) to open (“passing”) at thebeginning of third phase. Thus, the poppet valves CV1 and CV3 are closedduring most of the first phase and all of the second phase. Further, thepoppet valves CV1 and CV3 are open during most of the third phase andall of the fourth phase.

Conversely, lines 422 and 424 show that the poppet valves CV2 and CV4,respectively, are transitioned from closed (“not passing”) to open(“passing”) at the beginning of the first phase and then the poppetvalves CV2 and CV4 are transitioned from open (“passing”) to closed(“not passing”) at the beginning of third phase. Thus, the poppet valvesCV2 and CV4 are open during most of the first phase and all of thesecond phase. Further, the poppet valves CV2 and CV4 are closed duringmost of the third phase and all of the fourth phase.

FIG. 12 is a flow diagram of a method 500 performed by the controlsystem 220. The method 500 at least partially implements the VPSAprocess. As the method 500 is performed, the pressure transducer PT2(see FIGS. 7A and 7B) occasionally obtains pressure values for theadsorption bed 300 and sends the electrical pressure signal 374 to thecontrol system 220.

In first block 502, the control system 220 begins the first phase of theVPSA process by opening the poppet valves CV2 and CV4, and closing thepoppet valves CV1 and CV3. At this point, the pressure regulator R2 isclosed.

In next block 504, the control system 220 instructs the motor 350 of thecompressor 302 to pump the air 114 from the patient air intake 116 intothe adsorption bed 300. The motor 350 of the compressor 302 may run at arelatively high speed while drawing the air 114 from the patient airintake 116.

In block 506, the control system 220 determines that the pressure insidethe adsorption bed 300 has reached the first threshold pressure value(e.g., approximately 10 PSIG). When the pressure inside the adsorptionbed 300 reaches the first threshold pressure value, the pressureregulator R2 automatically opens. At this point, the first phase endsand the second phase begins. During the second phase, nitrogen isadsorbed by the adsorption bed 300 from the air 114 and referring toFIG. 8B, the oxygen 346 (e.g., 90% pure oxygen) flows out of theadsorption bed 300 through the pressure regulator R2. The oxygen thatpasses through the pressure regulator R2 during the second phase isstored in the oxygen tank 312.

Returning to FIG. 12 , in next block 508, at the start of the secondphase, the control system 220 reduces the speed of the motor 350.Referring to FIG. 8B, during the second phase, a mass transfer zone 430moves away from the first end 341 (in a direction identified by an arrow“D1”) through to the second end 343. Gas on a first side 432 of the masstransfer zone 430 near the first end 341 is air, and gas on a secondside 434 of the mass transfer zone 430 near the second end 343 is about90% oxygen. The compressor 302 may run relatively slowly during thesecond phase to facilitate effective nitrogen adsorption. In block 510,the control system 220 detects the end of the second phase, which endswhen the mass transfer zone 430 reaches the second end 343. The controlsystem 220 may determine the second phase has ended after apredetermined amount of time (e.g., about one second) has elapsed. Insome embodiments, the control system 220 may also use a secondary means(e.g., pressure) to help determine when the second phase has ended. Atthis point, the adsorption bed 300 is fully saturated with nitrogen, thesecond phase ends, and the third phase begins.

At the start of the third phase, in block 512, the control system 220opens the poppet valves CV1 and CV3, and closes the poppet valves CV2and CV4. At this point, the pressure regulator R1 is closed.

In next block 514, the control system 220 instructs the motor 350 of thecompressor 302 to pump the nitrogen-rich gas 122 from the adsorption bed300 and into the external environment through the outlet vent 124. Thecompressor 302 may run at a relatively high speed as it draws thenitrogen-rich gas 122 out of the adsorption bed 300.

In block 516, the control system 220 determines that the pressure insidethe adsorption bed 300 has reached the second threshold pressure value(e.g., approximately −7 PSIG). At this point, the third phase ends andthe fourth phase begins.

At the beginning of the fourth phase, in block 518, the control system220 may reduce the speed of the motor 350 to a relatively slow speed.

In block 520, the control system 220 purges the adsorption bed 300 withoxygen from the oxygen tank 312. In block 520, the pressure regulator R1opens automatically to allow the flow of “purge” oxygen 348 (see FIG.8D) from the oxygen tank 312 to flow through the adsorption bed 300(e.g., in a direction identified by an arrow “D2”). The mass transferzone 430 also moves away from the second end 343 (in a directionidentified by an arrow “D2”) through to the first end 341. The lowpressure inside the adsorption bed 300 combined with the flow of purgeoxygen 348 draws the nitrogen out and regenerates the adsorption bed300. When the purge is completed, the fourth phase ends, which completesone four-phase cycle, and the method 500 terminates. The control system220 may begin another cycle by returning to block 502 of the method 500.

FIGS. 13A-13D are schematic diagrams of the second rotary valve assembly330. The second rotary valve assembly 330 may be substantially similarto the first rotary valve assembly 306 (see FIGS. 10A and 10B). However,the second rotary valve assembly 330 includes a cam 530 with a singlelobe or high point 532, which is unlike the cam 850 of the first rotaryvalve assembly 306, which has two high points 910 and 912 (see FIG. 10F)opposite one another.

Referring to FIGS. 13A-13D, the cam 530 of the second rotary valveassembly 330 is configured to selectively actuate four poppet valvesCV5-CV8 one at a time. Each of the poppet valves CV5-CV8 may besubstantially similar to the poppet valve CV1 illustrated in FIG. 10E.

In the second rotary valve assembly 330, the poppet valves CV5 and CV7are positioned opposite one another. Similarly, the poppet valves CV6and CV8 are positioned opposite one another. The poppet valves CV5-CV8are biased into a closed position. Each of the poppet valves CV5-CV8 hasa pushrod 538 (substantially similar to the pushrod 880 depicted in FIG.10E) with a cam follower 540 (substantially similar to the cam follower883 depicted in FIG. 10C) that abuts the cam 530. As the cam 530rotates, it pushes only one of the pushrods 538 of the poppet valvesCV5-CV8 at a time outwardly and into an open position.

Further, as explained above with respect to the first rotary valveassembly 306, each of the poppet valves CV5-CV8 may include a poppetmember (substantially identical to the poppet member 892) configured tomove with respect to a seat (substantially identical to the seat 896) toselectively connect a proximal chamber (like the proximal chamber 900)with a distal chamber (like the distal chamber 902). In suchembodiments, after the cam 530 pushes the pushrod 538 of a selected oneof the poppet valves CV5-CV8 outwardly, the selected poppet valve opens.

Referring to FIG. 7B, the second rotary valve assembly 330 includes astepper motor 542 and a position sensor 544 substantially similar to thestepper motor 833 and the position sensor 834 of the first rotary valveassembly 306. The second rotary valve assembly 330 (e.g., the steppermotor 542) is configured to receive a control signal 546 from thecontrol system 220 encoding a cam position. The second rotary valveassembly 330 (e.g., the stepper motor 542) is also configured to rotatethe cam 530 to the position encoded in the control signal 546. Theposition sensor 544 provides a position signal 548 to the control system220 that encodes whether the stepper motor 542 and/or the cam 530 is ina home position (e.g., true or “on”) or at a position other than thehome position (e.g., false or “off”).

Referring to FIG. 13A, the poppet valve CV5 has an inlet 550 connectedto the suction connection 150 and an outlet 552 connected to the poppetvalve CV3 (see FIGS. 10D, 10F, and 10G). When the poppet valves CV1 andCV3 are open, the poppet valve CV5 may be opened (as shown in FIG. 13A)to receive the suction 154 from the compressor 302 and provide thesuction 154 to the suction connection 150. Any gases received from thesuction assembly 152 (see FIG. 1 ) via the suction connection 150, maybe pumped by the compressor 302 out the outlet vent 124 via the poppetvalve CV1. The nitrogen-rich gas 122 may be pumped by the compressor 302at the same time the suction 154 is provided.

Referring to FIG. 13B, the poppet valve CV6 has an inlet 554 connectedto the nebulizer assembly 162 and an outlet 556 connected to the poppetvalve CV2. When the poppet valves CV2 and CV4 are open, the poppet valveCV6 may be opened (as shown in FIG. 13B) to provide the gases 164 to thenebulizer connection 160 instead of providing the air 114 to theadsorption bed 300. Thus, the compressor 302 may power the nebulizerassembly 162 (see FIG. 1 ).

Referring to FIG. 13C, the poppet valve CV7 has an inlet 558 connectedto the metering valve 320 and an outlet 560 connected to the accumulator202. When the poppet valve CV7 is open as shown in FIG. 13C, oxygenoutput from the metering valve 320 is provided to the accumulator 202.

Referring to FIG. 13D, the poppet valve CV8 has an inlet 562 connectedto the metering valve 320 and an outlet 564 connected to the patientcircuit 110. When the poppet valve CV8 is open as shown in FIG. 13D, theoxygen 364 (from the adsorption bed 300) and/or the oxygen from theoxygen tank 312 is provided directly to the patient circuit 110.

Control System

Referring to FIGS. 5E and 7B, the control system 220 includes a memory700 connected to one or more processors 710. The memory stores the table362 and instructions 720 executable by the processor(s) 710.

The processor(s) 710 may be implemented by one or more microprocessors,microcontrollers, application-specific integrated circuits (“ASIC”),digital signal processors (“DSP”), combinations or sub-combinationsthereof, or the like. The processor(s) 710 may be integrated into anelectrical circuit, such as a conventional circuit board, that suppliespower to the processor(s) 710. The processor(s) 710 may include internalmemory and/or the memory 700 may be coupled thereto. The presentinvention is not limited by the specific hardware component(s) used toimplement the processor(s) 710 and/or the memory 700.

The memory 700 is a computer readable medium that includes instructionsor computer executable components that are executed by the processor(s)710. The memory 700 may be implemented using transitory and/ornon-transitory memory components. The memory 700 may be coupled to theprocessor(s) 710 by an internal bus 715.

The memory 700 may include random access memory (“RAM”) and read-onlymemory (“ROM”). The memory 700 contains instructions and data thatcontrol the operation of the processor(s) 710. The memory 700 may alsoinclude a basic input/output system (“BIOS”), which contains the basicroutines that help transfer information between elements within theventilator 100.

Optionally, the memory 700 may include internal and/or external memorydevices such as hard disk drives, floppy disk drives, and opticalstorage devices (e.g., CD-ROM, R/W CD-ROM, DVD, and the like). Theventilator 100 may also include one or more I/O interfaces (not shown)such as a serial interface (e.g., RS-232, RS-432, and the like), anIEEE-488 interface, a universal serial bus (“USB”) interface, a parallelinterface, and the like, for the communication with removable memorydevices such as flash memory drives, external floppy disk drives, andthe like.

The processor(s) 710 is configured to execute software implementing theVPSA process (which may include performing the method 500 illustrated inFIG. 12 ) and/or delivering oxygen in accordance with oxygen deliverymethods described below. Such software may be implemented by theinstructions 720 stored in memory 700.

Oxygen Delivery

Referring to FIG. 1 , as mentioned above, the ventilator 100 deliversthe inspiratory gases 108 directly to the patient connection 106 (viathe patient circuit 110). Oxygen may be delivered to the patient 102 inone of two ways: (1) as pulses of oxygen 140 delivered directly to thepatient connection 106, or (2) in the gases 112 that contain the air 114optionally blended with the oxygen 250 and/or the low pressure oxygen128 in the accumulator 202.

FIGS. 14A and 14B are graphs illustrating traditional delivery of oxygenby a conventional portable ventilator connected to an external lowpressure continuous flow source, such as a stand-alone oxygenconcentrator. In FIG. 14A, the conventional portable ventilator is usingtraditional volume controlled ventilation to deliver breaths. In bothFIGS. 14A and 14B, the x-axis is time. The inspiratory phase occursduring the duration T_(i). The exhalation phase occurs during a durationT_(E). The pause occurs during a duration T_(P).

In FIG. 14A, the y-axis is flow rate within the patient's airway.Referring to FIG. 14A, a dashed line 570 illustrates a continuous flowof oxygen delivered during both the inspiratory and expiratory phases. Asolid line 572 illustrates a flow of air provided by the conventionalportable ventilator during both the inspiratory and expiratory phases.The solid line 572 is determined by a set of desired ventilatorsettings.

An area 574 illustrates an inspiratory volume of air received by thepatient, and an area 575 illustrates an expiratory volume of airexpelled by the patient. The area 574 represents the desired total tidalvolume selected by the user.

A shaded area 576 illustrates a volume of effective oxygen provided tothe patient during the inspiratory phase. An area 578 illustrates avolume of oxygen that is delivered by the conventional portableventilator during the inspiratory phase but is unusable (e.g., trappedin one or more anatomical dead spaces). Together the areas 576 and 578form a volume of gases that exceed the desired ventilator settings(e.g., a desired total tidal volume). Specifically, together the areas574, 576, and 578 form a total inspiratory volume (of oxygen and air)delivered by the conventional portable ventilator that exceeds thedesired total tidal volume. An area 580 illustrates a volume of oxygendelivered by the conventional portable ventilator during the exhalationphase that is wasted by the conventional portable ventilator.

In FIG. 14B, the conventional portable ventilator is using traditionalpressure controlled ventilation to deliver breaths. Referring to FIG.14B, the y-axis is pressure within the patient's airway. A pressurevalue “PIP” identifies the peak inspiratory pressure input or desired bythe user. A solid line 581 illustrates patient airway pressure duringboth the inspiratory and expiratory phases. Unfortunately, as FIG. 14Billustrates, the continuous flow of oxygen (illustrated in FIG. 14A bythe dashed line 570) causes the pressure within the patient's airway toexceed the peak inspiratory pressure input by the user (the pressurevalue “PIP”).

As shown in FIGS. 14A and 14B, the conventional portable ventilator isinefficient. For example, the conventional portable ventilator wastesall of the continuous flow of oxygen (illustrated in FIG. 14A by thedashed line 570) delivered during non-inspiratory time. Further, becausethe continuous flow of oxygen delivered to the patient is not controlled(e.g., by ventilator volume or inspiratory pressure settings), only aportion of the oxygen (illustrated by the shaded area 576) delivered isactually effective. Further, the continuous flow of oxygen causes thepeak inspiratory pressure input by the user to be exceeded when pressurecontrolled ventilation is used. One reason for this problem is that theconventional ventilator does not know how much oxygen (e.g., volume orrate) is being delivered to the patient.

While FIGS. 14A and 14B depict the conventional portable ventilatorusing traditional volume controlled ventilation and traditional pressurecontrolled ventilation, respectively, to deliver breaths, a similarresult occurs when the conventional portable ventilator uses other typesof ventilation because the ventilator does not know how much oxygen(e.g., volume or rate) is being delivered to the patient. Thus, theventilator cannot accurately configure the breaths delivered (e.g., toachieve either a desired flow rate or pressure in the patient's airway).

FIGS. 15A and 15B are graphs illustrating oxygen delivery provided bythe ventilator 100 illustrated in FIGS. 1 and 4 . In FIG. 15A, theventilator 100 is using volume controlled ventilation to deliverbreaths. In both FIGS. 15A and 15B, the x-axis is time. The inspiratoryphase occurs during the duration T_(i). The exhalation phase occursduring the duration T_(E). The pause occurs during the duration T_(P).

Referring to FIG. 15A, a solid line 582 illustrates a flow of airprovided by the ventilator 100 during both the inspiratory andexpiratory phases. The solid line 582 is determined by a set of desiredventilator settings (e.g., values entered via the user interface 200illustrated in FIG. 6 ). A shaded area 584 illustrates a volume ofeffective oxygen provided to the patient 102 at the beginning of theinspiratory phase. An area 586 illustrates a volume of air provided tothe patient 102 during the inspiratory phase. Together the areas 584 and586 form a total inspiratory volume (of oxygen and air) delivered by theventilator 100. As mentioned above, this volume is also referred to asthe total tidal volume. An area 588 illustrates an expiratory volume ofair expelled by the patient 102.

FIG. 15A illustrates delivering one of the pulses of oxygen 140 (seeFIG. 1 ) at the start of the inspiration phase before the gases 112 (seeFIG. 1 ) are provided. For example, the ventilator 100 may wait untilafter the pulse of oxygen has been delivered before delivering the gases112. Thus, at the start of each inspiration phase of each breath, thepatient 102 (see FIG. 1 ) may be receiving only the pulse (or bolus) ofoxygen from the ventilator 100. However, this is not a requirement. Inalternate embodiments, the flow of the gases 112 may begin before thedelivery of the bolus of oxygen has completed. In any event, the flow ofthe gases 112 are started before the end of the inspiration phase.

In FIG. 15B, the ventilator 100 is using pressure controlled ventilationto deliver breaths. Referring to FIG. 15B, the y-axis is pressure withinthe patient's airway. A solid line 589 illustrates patient airwaypressure during both the inspiratory and expiratory phases. As FIG. 15Billustrates, the pressure within the patient's airway does not exceedthe peak inspiratory pressure value input by the user (the pressurevalue “PIP”) using the pressure control input 237 (see FIG. 6 ).

As shown in FIGS. 15A and 15B, the ventilator 100 is more efficient thanthe conventional portable ventilator. For example, the ventilator 100does not provide a continuous flow of oxygen and therefore, avoidswasting oxygen during non-inspiratory times. Further, the totalinspiratory volume is in accordance with (and does not exceed) thedesired ventilator settings. And furthermore, the oxygen is delivered inthe first part of the breath where the oxygen provides betteroxygenation, as opposed to during the last part of the breath when theoxygen becomes trapped in the anatomical dead spaces. Further, becausethe ventilator 100 knows the total tidal volume delivered, theventilator 100 may configure the breaths not to exceed a user suppliedpeak inspiratory pressure value (e.g., when pressure ventilation isused). Thus, one of ordinary skill in the art through application of thepresent teachings could configure the ventilator 100 to deliver anydesired type of ventilation in which oxygen is delivered in the firstpart of the breath. Further, the delivery of the pulses of oxygen 140(see FIG. 1 ) may begin before the initiation of each breath.

Referring to FIG. 13D, for pulse dose delivery, the control system 220instructs the second rotary valve assembly 330 (via the control signal546 depicted in FIG. 7B) to rotate the cam 530 to open the poppet valveCV8. The inspiratory phase may be initiated by either the control system220 or the patient 102. After detecting the beginning of an inspiratoryphase, the control system 220 instructs the stepper motor 322 of themetering valve 320 to deliver a desired dose or pulse of oxygen to thepatient circuit 110, referred to as a “bolus.” Thus, the ventilator 100is configured to synchronize a bolus of oxygen with the patient'sbreathing. For example, the ventilator 100 may be configured to providethe volume (or bolus) of oxygen depicted by the area 584 of FIG. 15A.

The user interface 200 may be used to determine parameter values for thebolus. For example, if the oxygen flow equivalent input 244 (see FIG. 6) allows the user to select a numerical value (e.g., from 1 to 10), eachsuccessive number may represent an amount of “equivalent oxygenation”relative to a continuous flow of oxygen. For example, the number “2” mayprovide a bolus of oxygen at the beginning of a breath that wouldprovide oxygenation equivalent to a bleed-in flow of oxygen at twoliters per minute from an external source (e.g., the low pressure oxygensource 118 depicted in FIG. 1 ). By way of another non-limiting example,the user may select a numerical value within a predetermined range thatrepresents from about 0.2 liters per minute to about 9 liters per minutein increments of about 0.1 liters per minute.

Because at least some of the oxygen delivered using a hypotheticalcontinuous flow of oxygen is wasted, the control system 220 isconfigured to deliver an amount of oxygen in the bolus that is less thanan amount of oxygen that would be delivered by the continuous flow ofoxygen during the inspiration phase.

In alternate embodiments, the user may enter a pulse volume value usingthe oxygen pulse volume input 251 (see FIG. 6 ) that specifies the sizeof the bolus. The pulse volume value may be expressed in milliliters ora dimensionless value within a predetermined numerical range (e.g., from1 to 10). In such embodiments, each successive number may represent agreater amount of oxygen.

The control system 220 adjusts the delivery of the breath to account forthe bolus, and ensures that the breath is delivered in accordance withthe user setting of tidal volume (entered via the tidal volume input 242depicted in FIG. 6 ) or the peak inspiratory pressure value (e.g.,entered via the pressure control input 237 depicted in FIG. 6 ). By wayof a non-limiting example, the control system 220 may configure thebolus to have a volume that is less than about 75% of the total tidalvolume delivered. By way of another non-limiting example, the controlsystem 220 may configure the bolus to have a volume that is betweenabout 50% and about 75% of the total tidal volume delivered.

Further, the ventilator 100 is configured to adjust the parameter values(e.g., volume, pressure, etc.) of the inspiratory gases 108 to assurethe inspiratory gases 108 are delivered correctly. For example, if theuser (e.g., a clinician) uses the tidal volume input 242 (see FIG. 6 )to set the total tidal volume value to 500 ml, and the oxygen pulsevolume input 251 (see FIG. 6 ) to set the pulse volume value to 100 ml,the control system 220 will set the air delivery from the accumulator202 to 400 ml, thus providing the correct total volume (500 ml=400ml+100 ml) to the patient circuit 110.

The control system 220 may deliver a user-set bolus of oxygen (e.g., inthe gases 112 and/or the pulses of oxygen 140) to the patient connection106. The size of the bolus is controlled by the metering valve 320. Thecontrol system 220 reduces the flow of the gases 252 (see FIG. 5A) asmeasured by the internal flow transducer 212 (and encoded in the flowsignal 270 illustrated in FIG. 5E) to satisfy a user set tidal volumevalue (when volume ventilation is used) or a user set peak inspiratorypressure value (when pressure ventilation is used).

The total inspiratory flow rate and volume of the gases 112 (see FIG. 1) may be determined using the flow signal 270 (see FIG. 5E), and thepulse volume may be determined using the signal 358 (see FIG. 7B) andthe stepper position value (described above) of the metering valve 320.Further, the control system 220 controls the pulse (or bolus) volumeusing the control signal 360 (see FIG. 7B) sent to the stepper motor 322(see FIG. 7B) of the metering valve 320. The control system 220 sets theair delivery from the accumulator 202 using the control signal 278 (seeFIG. 5E) sent to the motor 272 of the blower 222.

Referring to FIG. 13C, for mixed oxygen delivery, the cam 530 of thesecond rotary valve assembly 330 is positioned so that the poppet valveCV7 is in the open position. The control system 220 determines theoxygen flow required at a given time to achieve a FI02 input by the user(e.g., via the FI02 input 246 depicted in FIG. 6 ). The FI02 may beexpressed within a range (e.g., about 21% to about 100%). The controlsystem 220 may use the control signal 360 (see FIG. 7B) to position themetering valve 320 to achieve the desired oxygen flow. The controlsystem 220 may use the oxygen concentration signal 276 (see FIG. 5E)from the oxygen sensor 227 to monitor the gases 252 that pass throughthe internal bacterial filter 230 and emerge as the gases 112.

Suction Assembly

Referring to FIG. 16 , the suction assembly 152 may include a filter800, a conventional suction canister 810, a conventional suctioncatheter 812, and tubing 820 configured to be connected to the suctioncatheter 812. The suction catheter 812 may be configured to be insertedinside the patient connection 106.

Referring to FIG. 1 , the suction assembly 152 provides a means to usethe suction 154 provided by the ventilator 100 to “vacuum” secretionsfrom the patient's airway. Referring to FIG. 10G, the control system 220positions the cam 850 of the first rotary valve assembly 306 to open thepoppet valves CV1 and CV3, and, referring to FIG. 13A, the controlsystem 220 positions the cam 530 of the second rotary valve assembly 330to open the poppet valve CV5. In this configuration, the compressor 302pulls gas and secretions from the suction catheter 812 (see FIG. 16 ),through the tubing 820 and into the suction canister 810 (see FIG. 16 )where the liquid secretions are trapped. The filter 800 (e.g., ahydrophobic filter) may be used to further prevent patient secretionsfrom entering the ventilator 100 through the suction connection 150.However, gas pulled into the ventilator 100 continues through the firstand second rotary valve assemblies 306 and 330, and enters thecompressor 302. The control system 220 controls the speed of the motor350 of the compressor 302 to achieve the user set suction pressure, asmeasured by the pressure transducer PT2.

Nebulizer Assembly

Referring to FIG. 1 , the nebulizer assembly 162 provides a means to usethe gases 164 provided by the ventilator 100 for delivering aerosolizedmedications to the patient's lung(s) 142. Referring to FIG. 10F, thecontrol system 220 positions the cam 850 of the first rotary valveassembly 306 to open the poppet valves CV2 and CV4, and, referring toFIG. 13B, the control system 220 positions the cam 530 of the secondrotary valve assembly 330 to open the poppet valve CV6. In thisconfiguration, gas flows from the compressor 302, through the first andsecond rotary valve assemblies 306 and 330, and on to the nebulizerassembly 162. The control system 220 controls the speed of the motor 350of the compressor 302 to maintain a desired pressure (e.g., about 12PSIG) as measured by the pressure transducer PT2. The first rotary valveassembly 306 may be cycled to synchronize medication delivery with theinspiratory phase as desired. In a manner similar to that used for pulsedose oxygen delivery, the control system 220 may compensate (or adjust)the breaths delivered to account for the additional volume delivered bythe nebulizer assembly 162.

Cough Assist

As mentioned above, a normal cough may be characterized as having aninsufflation phase followed by an exsufflation phase. During theinsufflation phase, the patient 102 (see FIG. 1 ) draws gases into thepatient's lung(s) 142 (see FIG. 1 ). During the exsufflation phase, thepatient 102 exhales at least a portion of the gases in the patient'slung(s) 142 (which may include secretions from the patient's lung(s)142) using a peak flow rate and a peak pressure that are both greaterthan that used during the exhalation phase of normal breathing. Theventilator 100 (see FIGS. 1 and 4 ) is configured to provide coughassist functionality that facilitates secretion clearance by creating anexhaled flow rate and/or pressure that simulates a normal cough.Referring to FIG. 6 , the user may use the activate cough assist input241 to instruct the ventilator 100 (see FIGS. 1 and 4 ) to switch from anormal breathing mode to a cough assist mode during which the coughassist functionality is used to perform a cough assist maneuver with thepatient 102 (see FIG. 1 ).

As mentioned above, the ventilation assembly 190 may include either thecough assist valve 204 or the cough assist valve 2000. Referring to FIG.5C, if the ventilation assembly 190 includes the cough assist valve 204,at the beginning of the insufflation phase, the control system 220places the cough assist valve 204 in the first configuration (FIGS. 5A,5C and 18A). Thus, the blower 222 can deliver the gas 252 to the mainventilator connection 104 in the same manner that a normal breath isdelivered. The control system 220 (see FIG. 5E) instructs the blower 222(using the control signal 1180) to deliver flow to achieve pressure inaccordance with the user input settings for insufflation andexsufflation pressure. These settings are usually for greater flow rateand/or pressure than used during a normal breath but that may not alwaysbe the case. In other words, the blower 222 adds energy to the gas 252(e.g., increases its flow rate and/or pressure) that exits the blower222 and flows into the blower-to-valve inlet 1004 of the cough assistvalve 204. The gas 252 flows through a portion of the cough assist valve204 and exits the cough assist valve 204 into the flow line 273 via theaperture 1010. The flow line 273 conducts the gas 252 to the mainventilator connection 104. The main ventilator connection 104 is coupled(e.g., directly or using a hose, flow line, conduit, or tube) to thepatient circuit 110 (see FIG. 1 ), which conducts the inspiratory gases108 to the patient connection 106, which in turn conducts theinspiratory gases 108 on to the patient 102. The inspiratory gases 108inflate the lung(s) 142 and raise the pressure to a desired insufflationpressure (see FIG. 26 ).

At the end of the insufflation phase, the control system 220 (see FIG.5E) instructs the cough assist valve 204 (using the control signal 1180)to transition to the second configuration (see FIGS. 5B, 5D, and 18B).The control system 220 also instructs the blower 222 (using the controlsignal 1180) to increase its speed to achieve a desired exsufflationpressure (see FIG. 26 ). This creates a high peak exsufflation flowrate. At the end of the exsufflation phase, if desired, the cough assistmaneuver may repeated.

If the ventilation assembly 190 includes the cough assist valve 2000(see FIGS. 34A and 34B) instead of the cough assist valve 204, at thebeginning of the insufflation phase, the control system 220 places thecough assist valve 2000 in the first configuration (see FIG. 34A). Thecontrol system 220 (see FIG. 5E) instructs the blower 222 (using thecontrol signal 1180) to apply a selected flow rate and/or pressure whichoften is greater than used during a normal breath. The gas 252 exits theblower 222 and flows into the blower-to-valve inlet 2004 of the coughassist valve 2000. The gas 252 flows through a portion of the coughassist valve 2000 and exits the cough assist valve 2000 into the flowline 273 via the aperture 2010. The flow line 273 conducts the gas 252to the main ventilator connection 104. The main ventilator connection104 is coupled (e.g., directly or using a hose, flow line, conduit, ortube) to the patient circuit 110 (see FIG. 1 ), which conducts theinspiratory gases 108 to the patient connection 106, which in turnconducts the inspiratory gases 108 on to the patient 102. Theinspiratory gases 108 inflate the lung(s) 142 and raise the pressure toa desired insufflation pressure (see FIG. 26 ). At the end of theinsufflation phase, the control system 220 (see FIG. 5E) instructs thecough assist valve 2000 (using the control signal 1180) to transition tothe second configuration (see FIG. 34B). The control system 220 alsoinstructs the blower 222 (using the control signal 1180) to increase itsspeed to achieve a desired exsufflation pressure (see FIG. 26 ). Thiscreates a high peak exsufflation flow rate. At the end of theexsufflation phase, if desired, the cough assist maneuver may repeated.

Referring to FIG. 26 , a line 1200 illustrates airway pressure duringboth the insufflation and exsufflation phases of a cough assist maneuverperformed using the ventilator 100. Referring to FIG. 26 , a line 1202illustrates airway flow rates during both the insufflation andexsufflation phases of a cough assist maneuver performed using theventilator 100.

Because the ventilator 100 combines both mechanical ventilation andcough assist functions into one device, it is desirable to use the sametubing for both ventilation and cough assist so the user does not haveto change tubing connections between operations. Keeping the tubingconnection intact may also provide one or more of the followingbenefits:

1. better maintenance of the patient's oxygenation level,

2. reduced likelihood of ventilator-associated pneumonia, and

3. reduced risks associated with possible errors of reconnection.

Unfortunately, prior art passive patient circuits are inadequate for usewith cough assist because they include a fixed leak valve that reducesthe negative pressure in the patient circuit during the exsufflationphase. This reduction in negative pressure causes an undesirablereduction in the flow rate from the patient's lungs, which in turncompromises secretion clearance.

The passive patient circuit 440 illustrated in FIG. 2B avoids thisproblem because the passive patient circuit 440 includes the valveassembly 448 or the valve assembly 1448 (see FIGS. 30-31C). When thepassive patient circuit 440 includes the valve assembly 448, theperipheral portion 473 of the leaf 470 of the valve assembly 448 isconfigured to transition or deflect from the open position (see FIG. 2D)to the closed position (see FIG. 2C) when the pressure inside thepassive patient circuit 440 (see FIG. 2B) is less than the thresholdamount (e.g., environmental pressure). When the peripheral portion 473of the leaf 470 is in the closed position depicted in FIG. 2C, the leaf470 blocks off the one or more openings 478 and isolates the chamber 474from the environment inside the passive patient circuit 440 (see FIG.2B). Thus, the leaf 470 prevents a flow of air into the passive patientcircuit 440 (through the one or more openings 478) while the patientcircuit pressure is less than the threshold amount (e.g., when thepatient circuit pressure is negative). The valve assembly 448 may becharacterized as being a positive pressure leak valve in embodiments inwhich the valve assembly 448 is open when the patient circuit pressureis positive and closed when the patient circuit pressure is negative.

Similarly, referring to FIGS. 31A and 31B, when the passive patientcircuit 440 (see FIG. 2B) includes the valve assembly 1448, theperipheral portion 1473 of the leaf 1470 of the valve assembly 1448 isconfigured to transition or deflect from the open position (see FIG.31B) to the closed position (see FIG. 31A) when the pressure inside thepassive patient circuit 440 (see FIG. 2B) is less than the thresholdamount (e.g., environmental pressure). When the peripheral portion 1473of the leaf 1470 is in the closed position depicted in FIG. 31A, theleaf 1470 blocks off the one or more openings 1478 and isolates thechamber 1474 from the environment inside the passive patient circuit 440(see FIG. 2B). Thus, the leaf 1470 prevents a flow of air into thepassive patient circuit 440 (through the one or more openings 1478)while the patient circuit pressure is less than the threshold amount(e.g., when the patient circuit pressure is negative). The valveassembly 1448 may be characterized as being a positive pressure leakvalve in embodiments in which the valve assembly 1448 is open when thepatient circuit pressure is positive and closed when the patient circuitpressure is negative.

When a passive patient circuit (e.g., the passive patient circuit 170,the passive patient circuit 440, and the like) that includes a suitablepassive leak valve (e.g., the leak valve 177, the valve assembly 448,the valve assembly 1448, and the like) is used, gas flows to the patient102 through the passive patient circuit during the insufflation phase.Some of the flow leaks out through the passive leak valve, and the resttravels into the patient's lung(s) 142 (see FIG. 1 ). If the ventilationassembly 190 includes the cough assist valve 204 (see FIGS. 5A-5D and17A-18B), at the end of the insufflation phase, the control system 220transitions the cough assist valve 204 to the second configuration (seeFIGS. 5B, 5D, and 18B), and increases the speed of the blower 222 toachieve a desired exsufflation pressure. On the other hand, if theventilation assembly 190 includes the cough assist valve 2000 (see FIGS.34A and 34B), at the end of the insufflation phase, the control system220 transitions the cough assist valve 2000 to the second configuration(see FIG. 34B), and increases the speed of the blower 222 to achieve adesired exsufflation pressure. A check valve component (e.g., the flap179, the leaf 470, the leaf 1470, and the like) of the passive leakvalve prevents external flow from entering the passive patient circuit.

Alternatively, the active patient circuit 600 illustrated in FIG. 3A maybe used during a cough assist maneuver. When the active patient circuit600 is used, the active exhalation valve assembly 604 is closed duringboth the insufflation and exsufflation phases. During the insufflationphase, the control system 220 closes the active exhalation valveassembly 604 by energizing or activates the solenoid valve SV6 (usingthe control signal 286), which connects the pressure of the gases 252(via the port 275B) to the pilot port 111C. During the exsufflationphase, the control system 220 de-energizes or deactivates the solenoidvalve SV6 (using the control signal 286), which connects the internalpressure of the accumulator A2 (or the pilot pressure) to the activeexhalation valve assembly 604. This causes the active exhalation valveassembly 604 to remain closed. The active exhalation valve assembly 604remains closed because the pilot pressure is higher than patientpressure, and (as explained above) the area of the double bellows member644 exposed to a pressure provided by the patient 102 (see FIG. 1 ) viathe patient connection 106 is less than an area exposed to the pressureof the pressure signal 109C. Thus, even if the two pressures are equal,the closed end 666 of the double bellows member 644 will move to orremain in the closed position against the seat 680. It is noted that inthe cough assist mode, the pressure in Accumulator A2 is set to zero. Atthe beginning of exsufflation, the patient pressure is higher thanpressure signal 109C, so the exhalation valve opens. This is beneficialsince it drops the pressure faster, and creates greater exsufflationflow. When the patient pressure drops below ambient, the activeexhalation valve assembly 604 closes, preventing ambient gas fromentering into the patient circuit.

Secretion Trap

During a conventional cough assist maneuver, the patient connection 106(e.g., a tracheostomy tube) is pneumatically connected by cough assisttubing (e.g., tubing having an inner diameter of about 22 mm) to a coughassist device. By way of a non-limiting example, the patient connection106 (e.g., a tracheostomy tube) may have an outer diameter of about 15mm and an inner diameter of about 8 mm. Current practice is to connectthe cough assist tubing to the patient connection 106 utilizing aconnector, such as a connector or adapter having an outer diameter of 22mm and an inner diameter of 15 mm. The connector may be straight, rightangled, flexible, or outfitted with a swivel connector. The connectorfunctions as an adaptor that transitions from the outside diameter(e.g., about 15 mm) of the patient connection 106 (e.g., a tracheostomytube) to the inside diameter (e.g., about 22 mm) of the cough assisttubing. Thus, the flow pathway from the patient connection 106 to thecough assist tubing includes an abrupt transition (e.g., from an innerdiameter of about 15 mm to an inner diameter of about 22 mm).

Unfortunately, currently available connectors used to connect thepatient connection 106 to the cough assist tubing (which is connected toa cough assist device) are not designed to trap secretions generated bya cough assist maneuver. It is common for patient secretions to exit thepatient connection 106 (e.g., a tracheostomy tube) during theexsufflation phase, collect in the connector, and travel back towardand/or into the patient connection 106 during the insufflation phase,which is not desired. This process is typically repeated several timesuntil the secretions eventually migrate into the cough assist tubing.Then, the cough assist tubing is removed and disposed of or cleaned.

FIG. 27 illustrates a secretion trap 1250 that may be used instead of aconventional connector to connect the patient connection 106 to a coughassist tube 1252 serving as or as part of the patient circuit 110.Alternatively, the secretion trap 1250 may be formed in an end 1254 ofthe cough assist tube 1252. In FIGS. 27 and 28 , the patient connection106 has been illustrated as a tracheostomy tube 1260 connected to apatient airway 1262 (see FIG. 28 ). The cough assist tube 1252 may beconnected to a conventional cough assist device (not shown).

Alternatively, the secretion trap 1250 may be used to connect thepatient connection 106 to the patient circuit 110 (e.g., the passivepatient circuit 440, the active patient circuit 600, and the like)directly or using a hose, flow line, conduit, or tube. In suchembodiments, the patient circuit 110 is connected to the main ventilatorconnection 104 (and optionally to the patient oxygen outlet 105).Alternatively, the secretion trap 1250 may be implemented as a componentof the patient circuit 110.

In the embodiment illustrated, the secretion trap 1250 has a first endportion 1256 opposite a second end portion 1258. The first end portion1256 is couplable to the patient connection 106, and the second endportion 1258 is couplable to the cough assist tube 1252 or the patientcircuit 110 (see FIG. 1 ).

Referring to FIG. 28 , unlike conventional connectors (that may be usedto connect the patient connection 106 to the cough assist tube 1252),the secretion trap 1250 is configured to trap patient secretions 1268during a cough assist maneuver. Referring to FIG. 27 , internal geometryof the secretion trap 1250 is configured to create first and secondinner diameter steps. The first step transitions from an inner diameter“ID1” of the patient connection 106 (e.g., about 8 mm) to asignificantly larger inner diameter “ID2” (e.g., greater than about 22mm) of the secretion trap 1250. The second step transitions from theinner diameter “ID2” to a smaller inner diameter “ID3” (e.g., about 15mm). The second end portion 1258 of the secretion trap 1250 has an outerdiameter “OD” (e.g., about 22 mm) configured to mate with the coughassist tube 1252.

The small inner diameter “ID1” causes exsufflation flows (identified byan arrow 1270 in FIG. 28 ) to have a high first velocity that mobilizessecretions. The first (rapid) step to the larger inner diameter “ID2”causes the velocity of the exsufflation flows to reduce to a slowersecond velocity. This reduction in velocity causes the secretions 1268(see FIG. 28 ) to settle or collect in a well 1274 created by the largerinner diameter “ID2.” The well 1274 protects the secretions 1268 (seeFIG. 28 ) from re-mobilization during inspiratory flows (identified byan arrow 1272 in FIG. 28 ). Further, patient secretions typically have ahigh surface tension that helps retain them in the well 1274 until theycan be removed, which helps prevent contamination of the cough assisttube 1252 or the patient circuit 110 (see FIG. 1 ).

As mentioned above, because a cough assist maneuver may move secretionsduring both the exsufflation and insufflation phases, some secretionsmay remain within the patient connection 106 after the cough assistmaneuver. For this reason, the patient connection 106 is often suctionedto remove these remaining secretions after the cough assist maneuver.

FIG. 29 illustrates the secretion trap 1250 connected to a drain 1280configured to provide suction during a cough assist maneuver. Thus, thesecretion trap 1250 may be used to provide an improved therapy in whichthe secretions 1268 are suctioned as they exit the patient connection106 during a cough assist maneuver. The drain 1280 includes anopen-ended tube section 1282 having a first end portion 1284 in fluidcommunication with the well 1274, and a second end portion (not shown)in fluid communication with a suction device (e.g., the suction assembly152 illustrated in FIGS. 1 and 16 ). The first end portion 1284 may bepositioned nearer the patient connection 106 than the cough assist tube1252 or the patient circuit 110 (see FIG. 1 ). The suction deviceprovides negative pressure (depicted as an arrow 1290) to the drain 1280during a cough assist maneuver that suctions the secretions 1268 fromthe well 1274. The negative pressure draws the secretions 1268 into theopen-ended tube section 1282 (via its first end portion 1284) as thesecretions exit the patient connection 106, thereby keeping theventilation airway (e.g., the patient circuit 110) clear of secretionsthat may impede ventilation.

While the drain 1280 has been described and illustrated as beingconnected to the secretion trap 1250, in alternate embodiments, thedrain 1280 may be connected to other structures at or near the patientconnection 106. For example, the drain 1280 may be connected directly tothe patient connection 106. Alternatively, the drain 1280 may beconnected to the patient circuit 110.

The drain 1280 may provide one or more of the following features:

-   -   1. improved clearance of the ventilation airway,    -   2. reduced contamination, and    -   3. reduced need to disconnect the patient connection 106 from        mechanical ventilation (e.g., provided by the ventilator 100).        Because the drain 1280 provides secretion clearance without        disconnecting the patient circuit 110 from the patient 102, the        drain 1280 may be particularly useful with the ventilator 100,        which is configured to provide both mechanical ventilation and        cough assist.

The foregoing described embodiments depict different componentscontained within, or connected with, different other components. It isto be understood that such depicted architectures are merely exemplary,and that in fact many other architectures can be implemented whichachieve the same functionality. In a conceptual sense, any arrangementof components to achieve the same functionality is effectively“associated” such that the desired functionality is achieved. Hence, anytwo components herein combined to achieve a particular functionality canbe seen as “associated with” each other such that the desiredfunctionality is achieved, irrespective of architectures or intermedialcomponents. Likewise, any two components so associated can also beviewed as being “operably connected,” or “operably coupled,” to eachother to achieve the desired functionality.

While particular embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art that,based upon the teachings herein, changes and modifications may be madewithout departing from this invention and its broader aspects and,therefore, the appended claims are to encompass within their scope allsuch changes and modifications as are within the true spirit and scopeof this invention. Furthermore, it is to be understood that theinvention is solely defined by the appended claims. It will beunderstood by those within the art that, in general, terms used herein,and especially in the appended claims (e.g., bodies of the appendedclaims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to inventions containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations. In addition, evenif a specific number of an introduced claim recitation is explicitlyrecited, those skilled in the art will recognize that such recitationshould typically be interpreted to mean at least the recited number(e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations).

Accordingly, the invention is not limited except as by the appendedclaims.

The invention claimed is:
 1. A system for providing respiratory therapyto a patient, comprising: an air source; an oxygen source; a patientconnection configured to interface with the patient; a patient circuitconfigured to fluidly couple the air source and the oxygen source to thepatient connection, the patient circuit having (i) a first lumenconfigured to direct air from the air source to the patient connection,and (ii) a second lumen configured to direct oxygen from the oxygensource to the patient connection; and a leak vent positioned in thepatient connection and/or the patient circuit, wherein the second lumenextends downstream of the leak vent.
 2. The system of claim 1 whereinthe second lumen is configured to reduce and/or prevent the oxygendirected from the oxygen source to the patient connection from leakingout of the leak vent by virtue of the second lumen extending downstreamof the leak vent.
 3. The system of claim 1 wherein the patientconnection includes the leak vent.
 4. The system of claim 3 wherein thepatient connection includes a patient mask.
 5. The system of claim 1wherein the patient circuit includes the leak vent.
 6. The system ofclaim 1 wherein the leak vent includes an opening configured to permitegress of gas from within the patient connection and/or the patientcircuit to an environment external to the system.
 7. The system of claim1 wherein the leak vent includes a leak valve.
 8. The system of claim 7wherein the leak valve is configured to permit air within the firstlumen to leak out of the patient circuit and/or the patient connectionand into an environment external to the system when the pressure withinthe patient circuit and/or the patient connection exceeds a pressure inthe environment external to the system.
 9. The system of claim 1 whereinthe first lumen and the second lumen extend to the patient connectionsuch that the air in the first lumen does not mix with the oxygen in thesecond lumen in the patient circuit.
 10. The system of claim 1, furthercomprising a ventilator, the ventilator including the air source and theoxygen source.
 11. The system of claim 1, further comprising aventilator, wherein the ventilator includes the air source, and whereinthe oxygen source is external to the ventilator.
 12. A system forproviding respiratory therapy to a patient, comprising: a patientconnection configured to interface with the patient; a patient circuitconfigured to fluidly couple an air source and an oxygen source to thepatient connection for delivering air and oxygen to the patient, thepatient circuit having (i) a first lumen configured to direct air fromthe air source to the patient connection, and (ii) a second lumenconfigured to direct oxygen from the oxygen source to the patientconnection; and a leak vent positioned in the patient connection and/orthe patient circuit, wherein the second lumen extends downstream of theleak vent.
 13. The system of claim 12 wherein the second lumen isconfigured to reduce and/or prevent the oxygen directed from the oxygensource to the patient connection from leaking out of the leak vent byvirtue of the second lumen extending downstream of the leak vent. 14.The system of claim 12 wherein the patient connection includes the leakvent.
 15. The system of claim 12 wherein the patient circuit includesthe leak vent.
 16. The system of claim 12 wherein the leak vent includesan opening configured to permit egress of gas from within the patientconnection and/or the patient circuit to an environment external to thesystem.
 17. The system of claim 12 wherein the leak vent includes a leakvalve.
 18. The system of claim 12 wherein the first lumen and the secondlumen extend to the patient connection such that the air within thefirst lumen does not mix with the oxygen within the second lumen in thepatient circuit.
 19. A system for providing respiratory therapy to apatient, comprising: a patient connection configured to interface withthe patient; a patient circuit configured to fluidly couple a first gassource and a second gas source to the patient connection for deliveringa first gas and a second gas to the patient, the patient circuit having(i) a first lumen configured to direct the first gas from the first gassource to the patient connection, and (ii) a second lumen configured todirect the second gas from the second gas source to the patientconnection; and a leak vent positioned in the patient connection and/orthe patient circuit, wherein the second lumen extends downstream of theleak vent.
 20. The system of claim 19 wherein the second lumen isconfigured to reduce and/or prevent the second gas directed from thesecond gas source to the patient connection from leaking out of the leakvent by virtue of the second lumen extending downstream of the leakvent.
 21. The system of claim 19 wherein the patient connection includesthe leak vent.
 22. The system of claim 21 wherein the patient connectionincludes a patient mask.
 23. The system of claim 21 wherein the secondlumen is configured to extend into the patient connection.
 24. Thesystem of claim 19 wherein the patient circuit includes the leak vent.25. The system of claim 19 wherein the leak vent includes an openingconfigured to permit egress of gas from within the patient connectionand/or the patient circuit to an environment external to the system. 26.The system of claim 19 wherein the leak vent includes a leak valve. 27.The system of claim 26 wherein the leak valve is configured to permitthe first gas within the first lumen to leak out of the patient circuitand/or the patient connection and into an environment external to thesystem when the pressure within the patient circuit and/or the patientconnection exceeds a pressure in the environment external to the system.28. The system of claim 26 wherein the system is configured to provide abreath to a patient having an inhalation phase and an exhalation phase,and wherein the leak valve is configured to permit the first gas withinthe first lumen to leak out of the patient circuit and into anenvironment external to the system during the inhalation phase and theexhalation phase.
 29. The system of claim 19 wherein the first lumen andthe second lumen are configured to isolate the first gas and the secondgas along at least a portion of the patient circuit.
 30. The system ofclaim 19 wherein the second lumen is positioned within the first lumen.31. The system of claim 19 wherein the first lumen and the second lumenextend to the patient connection such that the first gas within thefirst lumen does not mix with the second gas within the second lumen inthe patient circuit.
 32. The system of claim 19 wherein the second gasincludes oxygen.
 33. A method of providing respiratory therapy to apatient, comprising: delivering air to the patient via a first lumenextending between an air source and a patient connection; and deliveringoxygen to the patient via a second lumen extending between an oxygensource and the patient connection, wherein at least a portion of thesecond lumen is isolated from the first lumen, and wherein deliveringoxygen to the patient via the second lumen includes bypassing a leakvent in the first lumen and/or the patient connection.
 34. The method ofclaim 33 wherein bypassing the leak vent prevents and/or reduces theoxygen from leaking out of the leak vent.
 35. The method of claim 33wherein the second lumen extends downstream of the leak vent.
 36. Themethod of claim 33 wherein the patient connection includes the leakvent.
 37. The method of claim 33 wherein the leak vent includes anopening configured to permit egress of first gas from within the firstlumen and/or the patient connection to an environment external to thefirst lumen and/or patient connection.
 38. The method of claim 33wherein the leak vent includes a leak valve.